Some key UN Security Council members insisted Tuesday that the world body would resist Sudanese pressure to withdraw thousands of peacekeepers. US Ambassador Susan Rice said the United States is "gravely concerned by reports of intense aerial bombardment" - at least 28 bombing raids on Tuesday morning alone - by Sudanese forces on the outskirts of a rebel-held town in southern Darfur. Rice said Sudanese forces were bombing the town of Muhajeria, despite the withdrawal of rebel forces to more than 48 kilometers away. The rebels seized the town in mid-January. Sudanese forces often have bombed rebel areas in Darfur, contrary to the council's ban on military flights in the region. "The bombardment continues and the government of Sudan has prevented UNAMID personnel from moving into the area to investigate, impeding the freedom of movement of these personnel, which is a violation of the status of forces agreement between UNAMID and the government," she said.