Washington will toughen enforcement of existing sanctions; bar another 31 companies, including oil exporters, from US trade and financial dealings; and take aim at two senior Sudan government officials, they said.
From a US perspective, a new UN resolution would apply new multilateral financial sanctions against Sudan and the three newly targeted individuals and expand an existing arms embargo from individuals operating in Darfur to any sales to Sudan's government, a US official said.
Pattern of obstruction
"President Bashir's actions over the past few weeks follow a long pattern of promising co-operation while finding new methods of obstruction," Bush said in remarks prepared for delivery from the White House diplomatic reception room.
The Darfur conflict has cost at least 200,000 lives and forced more than 2m people from their homes, according to the UN, though Sudan contests those estimates, saying 9,000 people have died.
|The conflict in Darfur has displaced more than|
two million people from their homes [EPA]
Washington's sanctions will be effective from Tuesday even though US diplomats are launching an all-out effort to win support for a new UN resolution, including efforts to overcome possible Chinese resistance, a senior US official said.
Khartoum's hand has been strengthened by China, which has opposed US-led plans within the Security Council to use sanctions to force al-Bashir to accept a UN deployment.
China openly supplies arms to Sudan and buys more than half of the African state's oil output.
Separately, France has proposed opening a humanitarian corridor through Chad to bring relief to victims of the Darfur conflict.
Bernard Kouchner, the French foreign minister, made the announcement late on Monday in in the northern German city of Hamburg. After talks with his Chinese counterpart, he said: "We are mulling several options, including securing a humanitarian corridor from Chad."
Kouchner said he had discussed the French proposal with Ban Ki-moon, the UN secretary-general, on Monday before bringing it to the eighth Asia-Europe meeting (Asem) in Hamburg.
French diplomats said the operation would be carried out by an international force with a UN mandate and could include French troops stationed in Chad, Sudan's western neighbour.
A source close to Kouchner said the bulk of the humanitarian force was likely to be made up of European troops, and that it would operate with the help of some 7,000 AU troops deployed in Darfur.