The lawmakers were expected to overwhelmingly back the motion giving the government another year-long mandate for cross-border operations against the outlawed Kurdistan Workers' Party (PKK).

Apart from the Democratic Society Party, the country's main Kurdish political movement, all parties support striking at the rebels inside their Iraqi strongholds amid nationwide outrage over Friday's deadly attack on a military outpost near the border.

In what was the bloodiest fighting this year, a large group of rebels used the cover of heavy weapons fire from northern Iraq in their strike in Hakkari province.

Ensuing clashes killed twenty-three militants, the army said.

Security operations intensified inside Turkey after the assault and four militants were killed in Sirnak province late Tuesday, while a wounded soldier died in hospital in Diyarbakir, officials said Wednesday.

Speaking ahead of the parliamentary vote, Prime Minister Recep Tayyip Erdogan stressed Turkey's right to self-defence and said Ankara would launch a cross-border incursion if necessary to rout the rebels.

Such an operation will be carried out "if need be, at the right time and under the right conditions with a view of obtaining the right result," Erdogan said Tuesday.

On Wednesday, Erdogan said officials would discuss calls to set up a military buffer zone inside northern Iraq along the border to stop rebel infiltrations, but signalled his reluctance about the move, proposed by a nationalist opposition party.

"We will discuss this with the armed forces and if it is really necessary, we will take this step," Erdogan told reporters.

The army last week also said a buffer zone would be difficult to maintain because it would require a large number of troops and pose logistical hardships to sustain them.

Under the current mandate that expires October 17, the Turkish army has carried out several air strikes in northern Iraq as well as a week-long ground incursion in February.

The operations were backed by intelligence from the United States which nonetheless fears that a large-scale Turkish intervention could destabilise Iraq's relatively calm north.

Since January, Turkish forces have killed 640 PKK militants, about 400 of them in cross-border operations in northern Iraq, according to army figures.

Ankara charges that about 2,000 PKK rebels are holed up in the autonomous enclave where, it says, they enjoy free movement, are tolerated by the region's Kurdish leaders and obtain weapons and explosives for attacks in Turkey.

Iraqi authorities have repeatedly pledged to curb the PKK, but say the group takes refuge in mountainous regions difficult to access.

The PKK -- considered a terrorist group by Turkey, the United States and the European Union -- has been fighting for self-rule in the mainly Kurdish southeast and east of Turkey since 1984. The conflict has claimed some 44,000 lives.