Turkey hit back with cross-border air strikes on rebel bases and sent troops into neighbouring Iraq as Prime Minister Recep Tayyip Erdogan cancelled a foreign trip and called an emergency meeting of top security officials.

The attacks by Kurdistan Workers' Party (PKK) rebels on the Turkish troops occurred in eight locations in Cukurca and Yuksekova in Hakkari province near the Iraqi border in the early hours of Wednesday, local security sources said.

"According to the latest confirmed information from Cukurca, the conflict region, 24 of our soldiers fell martyr and 18 of them were wounded," Erdogan said in televised remarks.

"Currently, large-scaled operations including hot pursuit (of rebels in Iraq) go on in accordance with the international law," said Erdogan, who cancelled an official visit to Kazakhstan in order to tackle the crisis.

The toll -- earlier put at 26 by health officials in Turkey's southeast -- is the heaviest for the army since 1993, when the PKK killed 33 unarmed soldiers in Bingol province, in southeast Turkey.

Several hundred Turkish soldiers have crossed into northern Iraq to hunt down PKK rebels, Kurdish news agency Firatnews said.

"Turkish soldiers from two separate points in Cukurca town crossed into south Kurdistan to follow (rebels)," said Firat news agency, which is known as a mouthpiece of the PKK.

A PKK spokesman, Dozdar Hammo, told AFP that Turkish troops "are attempting to cross the Iraqi border at Jeli," in the southeastern Hakkari region.

Turkish army commandos had been flown in by helicopter to the Iraqi side of the border, local security sources said.

Meanwhile, Turkish air force planes bombed Kurdish rebel bases in Iraq in retaliation for the attacks, security sources said.

The air raids targeted Qandil region, the main rear base of the PKK, and Zap region, they added.

Turkey has bombed rebel bases in Iraq several times in recent months, killing nearly 100 rebels, according to the army general staff.

Parliament in Ankara aarlier this month renewed the government's mandate to conduct ground incursions into Iraq.

"Both our friends and enemies should understand well that we will never give in to any attacks from inside or outside, never step back and sacrifice even one scrap of the land," Erdogan said.

He was speaking after gathering his top security officials, including the interior and defence ministers and military planners, in his office in Ankara.

President Abdullah Gul said on television that Turkey "will not be shaken by terror ... We will do whatever we can do to finish this."

"Those who believe they have shaken our state with those attacks... should know that the revenge for those attacks will be huge."

NATO also condemned the attacks.

"On behalf of NATO, I condemn in the strongest possible terms the recent attacks in southeastern Turkey, which killed and injured several Turkish soldiers, policemen and civilians, including a child," its secretary general Anders Fogh Rasmussen said.

Clashes between the PKK and the army have escalated since the summer.

Five police and four civilians were killed in a landmine explosion in the southeast on Tuesday.

The PKK, listed as a terrorist organisation by Turkey and much of the international community, took up arms in Kurdish-majority southeastern Turkey in 1984, sparking a conflict that has claimed about 45,000 lives.