CHICAGO (AP) — Illinois U.S. Senate appointee Roland Burris plans to have a high-stakes showdown on Capitol Hill this week with Democratic leaders who continue to say he won’t be seated in Congress.

Dozens of black leaders and ministers organized by U.S. Rep. Bobby Rush gave Burris a rousing send-off Sunday at New Covenant Church on Chicago’s South Side. Burris took the stage to a crescendo of drums, organ music and applause as hundreds of supporters cheered his appointment.

“We are hoping and praying that they will not be able to deny what the Lord has ordained,” Burris said. “I am not hesitating. I am now the junior Senator from the state of Illinois. Some people may want to question that and that is their prerogative.”

Opponents say Burris’ appointment is tainted because it was made by Illinois Gov. Rod Blagojevich, who is accused by federal authorities of offering to sell the vacancy to the highest bidder.

Burris, a former state attorney general, says the appointment is legal and the governor had the authority to do it. He has threatened to sue Senate Democrats if they refuse to swear him in as the chamber’s only black member.