Turkey moved across its border with Iraq seven days ago to track fighters from the Kurdistan Workers' party (PKK) to their bases in the northern Iraqi mountains.
Conflicting reports have indicated there are rising casualties on both sides.
"The jury is out, frankly, as to who is winning this conflict because the Turkish military's claims about the fighting are worlds apart from those of the PKK," Laurence Lee, Al Jazeera's correspondent, reported from Ankara.
He said Turkey was carefully managing its media's reporting of the conflict.
On Wednesday pictures emerged which appear to substantiate claims by PKK fighters that they shot down a Turkish helicopter on Saturday in the remote Chamsku region of Iraq.
"We got those pictures today of the destroyed helicopter which the PKK claimed days ago that they shot down - it took a very long time for the Turks to even admit they had lost that helicopter," said Lee.
Turkey's military general staff said another 77 PKK fighters had been killed since Tuesday night, taking the death toll among the PKK to 230 since Turkey's offensive began.
The PKK claims that 81 Turkish troops have been killed, but casualty numbers could not be verified.
Turkey's refusal to set a timetable for withdrawal comes after Robert Gates, the US defence secretary, urged Turkey to quickly end its military operation in Iraq.
US calls for swift resolution
Gates told reporters in the Indian capital New Delhi that the US wants Ankara to adopt a different method of dealing with fighters from the PKK.
"It's very important that the Turks make this operation as short as possible and then leave, and to be mindful of Iraqi sovereignty," Gates said.
"I measure quick in terms of days, a week or two, something like that. Not months," he said.
Gates is expected to arrive in Ankara, the Turkish capital, later on Wednesday.
In Turkey, more than 40 military trucks ferried hundreds of commandos towards the Iraqi border, a day after heavy snow slowed down Turkey's offensive.
F-16 warplanes were seen flying over the border town of Cukurca towards Iraq, while helicopters brought dozens of troops to a base on the outskirts of the town.
Some helicopters also headed toward Iraq.
The Iraqi government has condemned Turkey's incursion into the Kurdish north of the country.
A statement from Baghdad on Tuesday said that the move was a violation of Iraq's sovereignty and demanded an immediate cessation of fighting.
Ali al-Dabbagh, an Iraqi government spokesman, said: "The cabinet ... expressed its rejection and condemnation of the Turkish military incursion which is considered a violation of Iraq's sovereignty."
Members of the Kurdish security force in the autonomous north of Iraq told the AFP news agency that sustained fighting had continued since Sunday as troops, backed by artillery and air cover, fought to seize a PKK camp in the Zap area.
The camp, situated in a deep valley 6km from the Turkish border, is allegedly one of the main passages used by PKK fighters to infiltrate Turkish territory and launch attacks.
Ankara says an estimated 4,000 PKK rebels are holed up in northern Iraq using the region as a springboard for attacks on Turkish territory as part of their campaign for self-rule in the Kurdish-majority southeast of the country.
Large protests in support of the PKK turned violent in the town of Diyabakir on Monday as protesters clashed with police.
Al Jazeera's Hoda Abdel Hamid said the situation in the town was tense and that reports of similar small clashes in other Turkish towns reflected the growing frustration of Turkey's Kurdish minority.
She said that there was also growing anger on the Turkish side as the number of coffins of soldiers returning home continued to mount.