Speaking Tuesday at the White House, Bush said Sudanese President Omar Hassan al-Bashir had broken promises of allowing U.N. peacekeepers into the region and to stop using government troops in the violence against citizens.
"President Bashir's actions over the past few weeks follow a long pattern of promising cooperation while finding new methods for obstruction," Bush said in announcing the U.S. sanctions.
They include adding 30 companies to the Treasury Department's list of firms that will have assets frozen for doing business with the Sudanese government. Bush said yet to be identified individuals would be named in the sanctions, which make it a crime to knowingly doing business with Khartoum.
The president said he was also directing U.S. Secretary of State Condoleezza Rice to seek support from Britain and other allies to rally for stronger U.N. sanctions.
As many as 450,000 people have been killed since the fighting began in 2003 and more than 2.5 million were displaced, relief agencies report.