Washington  - Embattled Illinois Governor Rod Blagojevich appointed a replacement Tuesday for the US Senate seat vacated by president-elect Barack Obama, defying warnings from his own party that his choice would not be accepted because of the corruption charges against him.

Blagojevich named former Illinois Attorney General Roland Burris, 71, to the post, even as Senate Majority Leader Harry Reid and other Democrats said any Blagojevich candidate will not be viewed as credible and vowed they will not seat the successor.

"Anyone appointed by Governor Blagojevich cannot be an effective representative of the people of Illinois and, as we have said, will not be seated by the Democratic Caucus," Senate Majority Leader Harry Reid said in a statement.

Federal agents arrested Blagojevich on December 9 on numerous corruption charges, including a plot to solicit bribes from potential candidates to replace Obama.

"If I don't make this appointment then the people of Illinois will be deprived of their appropriate voice and vote in the United States Senate," Blagojevich, a Democrat, said in a press conference in Chicago.

Blagojevich, 52, has promised to fight the charges against him and steadfastly refuses to resign or relinquish his power to appoint a new senator despite the litany of corruption related allegations against him.

Federal agents alleged that in wiretapped conversations the governor discussed ways to use his power to pick a new senator for his personal benefit. The Illinois legislature has initiated impeachment proceedings against him, and the state's top election official has said he will not certify Blagojevich's pick.

Obama and other top Democrats had urged the Illinois state legislature to either hold a special election or strip Blagojevich of his authority to name the successor. The president-elect called the governor's move "extremely disappointing" and said he agreed with the Senate leadership's decision not to seat anyone named by the governor.

"While Governor Blagojevich is entitled to his day in court, the people of Illinois are entitled to a functioning government and major decisions free of taint and controversy," Obama said in a statement.

Reid praised Burris for his years of public service but said any choice made by Blagojevich was not acceptable.

"This is not about Mr Burris. It is about the integrity of a governor accused of attempting to sell this United States Senate seat," Reid said in a joint statement with other top Senate Democrats.

Blagojevich and his top aide, who has resigned, face up to 20 years in prison if convicted for wire fraud and conspiring to solicit bribes.

The Justice Department also accused the two men of threatening to withhold state assistance for a media firm, the Tribune Co, unless it sacked editorial writers seen as unfriendly to the (governo)r. They were additionally charged with seeking campaign ontributions in exchange for official actions in a "pay-to-play" scheme.

The scandal has also disrupted Obama and his transition team as the president-elect prepares to take office January 20. Obama last week released a report by his legal team of all contact between his staff and Blagojevich. The report concluded there was no inappropriate communications. Neither Obama or any staff were implicated in the investigation.

Burris became the first African-American to win Illinois statewide office in 1978, when he was elected comptroller. He later went on to serve as attorney general. (dpa)