US Defence Secretary Robert Gates has said Turkish operations in northern Iraq must end as soon as possible.
The Turkish military claims to have inflicted high rebel losses
Mr Gates, speaking ahead of a visit to Ankara, said US concerns about the assault against Kurdish militants had been made clear at the highest levels.
Separately, a Turkish envoy arrived in Iraq for talks, Iraqi sources said.
Turkish officials say 77 rebels were killed overnight, bringing the militant toll to 230 since the offensive began. Turkey had lost 24 soldiers, they said.
Five died in the latest clashes, as well as three pro-government "village guards".
The PKK rebels, who want a homeland in south-east Turkey, say they have killed at least 81 Turkish soldiers. Neither report can be independently verified.
Iraq has condemned the incursion into its territory and urged Turkey to withdraw its forces.
Speaking to the BBC in Delhi before leaving for Turkey, Mr Gates said the Turkish military operation against PKK bases should be very short and very precisely targeted.
Then, he added, the Turks should withdraw back across the border.
"They cannot solve the PKK terrorist problem which is a very real one from the Turks' standpoint," he said.
"A lot of innocent Turks have been killed by these terrorists. But they can't solve that problem entirely by military means and they need to begin thinking about what they're going to do in the non-military arena."
He said the US had provided additional intelligence and reconnaissance help to Turkey, but would also be ready to offer non-military solutions to the problem.
More than 30,000 people have been killed since the PKK began their campaign in 1984.
Ankara says as many as 3,000 PKK members use northern Iraq as a safe haven.
The US, the EU and Turkey consider the PKK to be a terrorist organisation.