The United States was likely to call a UN vote on Tuesday to impose sanctions on four Sudanese accused of war crimes in Darfur, despite opposition from China and Russia, a US official said. The sanctions, a travel ban and a freeze on assets abroad, would be the first adopted against individuals involved in the Darfur conflict. They were authorised by the UN Security Council in March 2005 against those who thwart peace efforts, violate human rights or conduct military flights over Darfur. "We very well could vote," said Richard Grenell, spokesman for the US Mission to the United Nations. Russia and China believe the sanctions could interfere with the two-year-old Darfur peace talks between the Khartoum government and two rebels groups, conducted in Abuja, Nigeria. To ease the concerns of African nations, the Security Council expects to approve at the same time a Tanzanian-drafted statement supporting the Abuja talks. Africa Union mediators have set April 30 as a deadline for a new cease-fire deal.