Turkey's prime minister said Tuesday increased military action against separatist Kurdish rebels was "unavoidable" and pressed the United States for a crackdown on guerrilla bases in northern Iraq.

Turkish helicopters pounded rebel positions near the border with rockets for a second day and Turkey brought in troops by the truckload in an operation against mountainside emplacements.

Prime Minister Recep Tayyip Erdogan told members of his party in parliament "it is now unavoidable that Turkey will have to go through a more intensive military process."

But he also suggested he was not seeking an immediate cross-border offensive against the rebels of the Kurdistan Workers' Party, or PKK, holed up in bases in northern Iraq. "The responsibility of leadership does not allow for narrow mindedness, haste or heroism," he said.

"We must remember that Turkey is part of this world and diplomacy has certain requirements," Erdogan added, suggesting the world expected Turkey to exhaust all nonmilitary options.

Erdogan flies to Washington on Nov. 5 for talks with President Bush that could be key to whether Turkey carries out its threat of a major military incursion. Secretary of State Condoleezza Rice is also expected in Turkey later this week.

"We will openly express that we expect urgent steps from the United States, which is our strategic partner and ally and has a special responsibility regarding Iraq," Erdogan said.

The United States, Iraq and other countries have been calling on Turkey to refrain from a cross-border campaign, which could throw one of the few stable areas in Iraq into chaos. A Turkish incursion would also put the United States in an awkward position with key allies: NATO-member Turkey, the Baghdad government and the self-governing Iraqi Kurds in the north.

White House press secretary Dana Perino said Bush's discussions with Erdogan would include "the fight against terrorism _ in particular our joint efforts to counter the PKK."

Turkish Cobra attack helicopters blasted suspected PKK targets in the Mount Cudi area, near the southeastern border with Iraq for a second day, trying to hunt down some 100 rebels believed to be hiding in mountainside caves, the private Dogan news agency reported.

The fighting has claimed the lives of three Turkish soldiers and six guerrillas, local news reports said.

Transport helicopters flew in commando units to block possible rebel escape routes on Cudi, Dogan reported.

An AP Television News cameraman said attack helicopters escorted four Black Hawk helicopters on Cudi, as they airlifted soldiers to the mountain and picked others up. Smoke could be seen rising from areas that had been hit in the attacks.

Dogan reported a 100-vehicle military convoy traveling from Cizre toward the border.

A Kurdish political party warned that the fighting threatened to increase animosity between the Turkish and Kurdish populations in Turkey.

Turkey is "moving toward a dangerous war in our region which will seriously damage historical relations between Turks and Kurds," Nurettin Demirtas, a senior party official, told reporters.

Erdogan's Cabinet scheduled a meeting for Wednesday to discuss possible economic measures against groups supporting the Kurdish rebels.

Deputy Prime Minister Hayati Yazici said Turkey was considering a series of sanctions against the self-governing Kurdish administration in Iraq's north.

Yazici would not give any details, but the Iraqi region is heavily reliant on Turkish electricity and food imports, as well as Turkish investment in construction. There has been talk of shutting down the Habur border crossing _ the only vehicular route into Iraq from Turkey.

Jamal Abdullah, a spokesman for the Iraqi Kurd regional government, complained that economic sanctions "would represent a collective punishment against Kurdistan's people."

He warned that Turkey and the U.S. Army also would suffer if the border crossing was closed. About 70 percent of U.S. air cargo headed for Iraq goes through Turkey, as does about one-third of the fuel used by the U.S. military there.

In an interview printed Tuesday in Turkey's Milliyet newspaper, Massoud Barzani, the leader of Iraq's Kurdish region, called for a peaceful solution to the crisis. He said that if the PKK did not give up violence, it would "confront not only Turkey but the whole Kurdish nation."

But he questioned Turkey's motives, suggesting it is interested in targeting not only the PKK but also Iraqi Kurds.

At least 46 people have been killed by the PKK in Turkey over the past month, according to government and media reports. Those included at least 30 Turkish soldiers killed in two ambushes that were the boldest attacks in years and increased domestic pressure on Erdogan to act.

A Brazilian judge has extended a term of temporary custody for six people connected with Cisco, the US technology giant accused of tax fraud, and imprisoned a further three people accused of involvement in the alleged scheme.

Some 40 people were arrested on October 16 after a two-year investigation involving police, public prosecutors and tax authorities. A former president and three serving senior executives of Cisco in Brazil, including its president, were held for five days. The former president was among six people retained in custody after the initial period and is among those held again on Friday.

Authorities say Cisco and its agents constructed a complex system of real and phantom companies to avoid import duties and other taxes amounting to R$1.5bn over the past five years. Cisco said it did not believe its employees had acted inappropriately and was co-operating with investigations.

In addition to Cisco executives, those arrested included employees of Cisco's main distributor in Brazil and of companies based at a technology park in Brazil's north-east. Also arrested were customs agents and tax inspectors.

Brazil, which is considered a key emerging market for Cisco along with Russia, India and China, accounts for about 1 per cent of Cisco's overall business, according to the company.

Officials said that over the past five years about 50 tonnes of goods had been imported each month under the alleged scheme at a declared total value of $500m. They said initial estimates put the amount of tax evaded at about R$1.5bn.

Former supermarket worker Alexander Pichushkin confessed to killing 63 people with the goal of marking each death on a chessboard, which has 64 squares.

Prosecutors last month charged him with 49 murders committed between 2001 and 2006 in a park on the edge of Moscow.

Though he claims to have killed several people years earlier, prosecutors had focused on the series of killings that occurred in Bittsa Park in 2001, leading to his nickname as the "Bittsa Maniac." Most of the victims were men, whom Pichushkin had lured to the park with the promise of a drink of vodka to mourn the death of his "beloved" dog.

Pichushkin allegedly killed 11 people in 2001, including six in one month, prosecutors said, adding that he killed about 40 of his first victims by throwing them into a sewage pit and in a few cases strangled or hit them in the head, prosecutors said.

From 2005, he began to kill with "particular cruelty," hitting his intoxicated victims multiple times in the head with a hammer, then sticking an unfinished bottle of vodka into their broken skulls, prosecutors have said. He also no longer tried to conceal the bodies, leaving them at the crime scene.

NASA gathered the information under an $8.5 million safety project, through telephone interviews with roughly 24,000 commercial and general aviation pilots over nearly four years. Since ending the interviews at the beginning of 2005 and shutting down the project completely more than one year ago, the space agency has refused to divulge the results publicly.

Just last week, NASA ordered the contractor that conducted the survey to purge all related data from its computers.

The Associated Press learned about the NASA results from one person familiar with the survey who spoke on condition of anonymity because this person was not authorized to discuss them.

A senior NASA official, associate administrator Thomas S. Luedtke, said revealing the findings could damage the public's confidence in airlines and affect airline profits. Luedtke acknowledged that the survey results "present a comprehensive picture of certain aspects of the U.S. commercial aviation industry."

The AP sought to obtain the survey data over 14 months under the U.S. Freedom of Information Act.

"Release of the requested data, which are sensitive and safety-related, could materially affect the public confidence in, and the commercial welfare of, the air carriers and general aviation companies whose pilots participated in the survey," Luedtke wrote in a final denial letter to the AP. NASA also cited pilot confidentiality as a reason, although no airlines were identified in the survey, nor were the identities of pilots, all of whom were promised anonymity.

Among other results, the pilots reported at least twice as many bird strikes, near mid-air collisions and runway incursions as other government monitoring systems show, according to a person familiar with the results who was not authorized to discuss them publicly.

The survey also revealed higher-than-expected numbers of pilots who experienced "in-close approach changes" — potentially dangerous, last-minute instructions to alter landing plans.

Officials at the NASA Ames Research Center in California have said they want to publish their own report on the project by year's end.