The United States will consider further sanctions against Sudan if it continues "dragging its feet" over accepting a U.N.-African Union peacekeeping force, a top U.S. official said on Thursday.

U.S. Ambassador Zalmay Khalilzad said Khartoum was holding up the deployment by not approving the proposed composition of the force, which he said was 75 percent African in total, with more than 90 percent of ground forces African.

The U.N. Security Council resolution on the force said it should be "predominantly African."

"This is, in our view, just excuses by the government, dragging its feet, part of the pattern one has seen with this government," Khalilzad told reporters.

"It's very important that quickly they embrace this proposed package, otherwise certainly the United States will be looking at measures to incentivize cooperation, and that includes further sanctions," Khalilzad said.

He said there were concerns over Khartoum's allocation of land to be used by the force, as well as other administrative issues such as access to ports and airfields.

Khalilzad also urged both the government and Darfur rebels to attend peace talks starting over the weekend, and said the Security Council could take action against those who obstructed the peace process.

One of several obstacles to the talks between the Khartoum government and rebels from Darfur in western Sudan has been the rebels' inability to agree a common platform.

"It's very important that everyone should go to this peace conference ... and those who don't will have to answer," Khalilzad said.

"I do not exclude the possibility that the council will take action, and you know what the range of options are, with regard to those who don't cooperate with the peace process."

International experts estimate 200,000 people have died and 2.5 million have been driven from their homes in the Darfur conflict, which began with a revolt against the Sudanese government, but Khartoum puts the death toll at 9,000.