Meanwhile, the Pentagon says it has started giving more intelligence - "lots of intelligence" - to Turkey to help it against the rebels.
The U.S. has in recent days sent U-2 spy planes to the border area to try to collect better information on the militants and regional Iraqi authorities have sent some of their troops there, one official said.
Turkey has complained for months about what it has said is a lack of U.S. support against the rebels from the Kurdistan Workers' Party, known by its Kurdish acronym PKK. And Ankara has threatened a full-scale ground attack into northern Iraq if the U.S. and Iraqi officials don't do something about the rebels.
"We have given them more and more intelligence as a result of the recent concerns," said Defense Department Press Secretary Geoff Morrell.
Also Wednesday, reports from Turkey said Prime Minister Recep Tayyip Erdogan had accused the leader of Iraq's Kurdish region of "aiding and abetting" the separatist rebels in a sign of growing frustration with Iraqi Kurds' refusal to crack down on them.
Erdogan's reported remarks about
He voiced fears that Ankara may be planning a wider campaign against the northern Kurdish region of Iraq instead of an operation targeting only rebels with the Kurdistan Workers' Party, or PKK.
Though Barzani's forces fought with Turkish troops against the rebels in previous incursions in the 1990s, Turkey has rejected dialogue with him since he made inflammatory statements about Turkey amid rising Kurdish nationalism after the invasion of Iraq.
Iraq's Foreign Minister Hoshyar Zebari said Iraq would set up checkpoints along the border with heavily Kurdish southeastern Turkey to stop fuel, food and other supplies from reaching the Iraq-based PKK, which has killed dozens of people inside Turkey over the past month. He said they would also take other unspecified measures against the rebels.
Zebari, who is Kurdish, told reporters that Iraq would also restrict the movement of PKK fighters in order to "prevent them from reaching the populated towns and areas" inside Turkey.
The Iraqi official's comments came after he discussed the border issue with Iranian Foreign Minister Manouchehr Mottaki in Baghdad.
In other developments:
Turkish helicopters have begun pounding rebel hideouts in Turkey with rockets, and Turkish Prime Minister Recep Tayyip Erdogan said Wednesday that his nation would exhaust all diplomatic options before ordering a cross-border offensive.
Zebari warned that a Turkish military incursion into northern Iraq would have "serious consequences for the entire region and could undermine its stability."
He said Iraq was ready "to cooperate actively with the Turkish government to find practical measures" to prevent the attacks staged by Kurdish rebels from Iraqi territory.
A Kurdish insurgent group affiliated with the PKK is also fighting for autonomy inside Iran.
Zebari pleaded with participants in a regional conference, planned for Saturday in Istanbul, to remain focused on the issue of Iraq's stability and security, rather than Turkey's threat of sending its military into suspected PKK strongholds in northern Iraq.
"This meeting is very important and should not be hijacked by the current tension and crisis over the PKK terrorist activities in Turkey," he said. "We want this meeting to focus on Iraq's stability and security."
At a May conference in Sharm el-Sheik, Egypt, Iraq's neighbors promised to stop foreign militants from joining Iraq's insurgency - a pledge that the United States says has not been met.
Turkey is also considering economic sanctions that could wreck the economy of Iraq's Kurdistan region, the most peaceful part of the country.
Kurdistan's regional government has significant autonomy and provides virtually all its own security in the three-province region.
Zebari has said the Iraqi government plans to present the Istanbul conference with recommendations in three key areas - security, refugees and energy.