Troops encircled an area near Iraq to try to stop insurgents from escaping across the border. Anger is heightening in Turkey over the ability of separatist fighters to seek asylum in Iraq.
Turkey has been pressing Iraq and the United States to hit bases of the rebel Kurdistan Workers' Party, or PKK, in northern Iraq, and has considered a military operation across the border to eradicate the rebels.
"Our government is determined to take every measure possible if it will be useful to stamp out terrorism," State Minister Cemil Cicek, the government spokesman, said at the end of a Cabinet meeting.
A statement released at the end of an emergency security meeting between Prime Minister Recep Tayyip Erdogan, President Abdullah Gul and the commander in chief of the armed forces, and Gen. Yasar Buyukanit, expressed determination to "press ahead with (the) rightful struggle against terrorism and to implement strong measures." It did not elaborate.
Earlier this year, the military opposed Gul's efforts to win the presidency because it feared he would impose Islamic values at the expense of Turkey's secular traditions; Gul, a pious Muslim, has vowed to safeguard secularism.
Erdogan said late Sunday he would discuss the PKK threat with U.S. President George W. Bush during a visit to Washington next month.
On Monday, a soldier was killed and three were injured when their vehicle hit a land mine believed to have been planted by rebels near Lice, southeast Turkey, the Anatolia news agency reported.
One soldier was killed in a separate explosion on a road in the southeastern province of Sirnak, the private Dogan news agency reported.
Sunday's casualties also occurred in Sirnak, where the 18-member commando unit was ambushed on the way to an operation on Mt. Gabar, some 25 kilometers (16 miles) northwest of the Iraqi border, Gov. Selahattin Apari said in an interview.
An operation to track down the rebels was under way, and troops shelled areas to try to prevent rebels from reaching bases in northern Iraq, the military said. The state-run Anatolia agency said the military was conducting anti-rebel offensives, backed by air power, in four regions inside Sirnak province.
"The operations are continuing nonstop, we are suffering (losses) because of the intensity of the anti-rebel operations," Apari said.
Apari said Sunday's attack was in retaliation to serious losses the rebels suffered at the hands of Turkish troops in recent months.
The rebels were mostly infiltrating into Turkey from the Beytussebap area, some 120 kilometers (75 miles) east of Sirnak, the governor said.
The ambushed commandos were transferred from a commando regiment in the western city of Bolu to help fight the rebels.
On the way to Sirnak _ the biggest city in the province of the same name _ Turkish commandos were manning a checkpoint as two armored personnel carriers stood by at the Kasrik crossing, one of the most mountainous areas in the rugged region. As some soldiers checked IDs of passengers, a Turkish soldier was seen with a heavy machine gun, placed on sandbags, directed at the mountains.
On Monday, at least two F-16 war planes could be seen taking off from Diyarbakir air base. Other war planes could be seen outside of hangars with their canopies open, ready to take off.
Abdul-Rahman al-Chadarchi, a spokesman for the Kurdish rebel group, confirmed the attack on Sunday and said the rebel fighters sustained no casualties.
Kurdish rebels have staged attacks on Turkey from their bases in northern Iraq. But the U.S. opposes any military move into Iraq by Turkey.
Turkey signed a counterterrorism pact with Iraq in September and had demanded it be allowed to send its troops to Iraq's north to pursue Kurdish rebels. But Iraq did not agree to the demand under pressure from the leaders of its semiautonomous Kurdish region.
"We are not concerned with this issue because these clashes and shelling happened inside Turkish territories. This is a Turkish internal problem," Jamal Abdullah, a spokesman for the government of Iraq's Kurdish region, said after Sunday's attack.
The PKK is branded a terrorist organization by the U.S. and the European Union. Its members have fought Turkish government forces since 1984, seeking autonomy for Turkey's ethnic Kurds. The fighting has claimed tens of thousands of lives.