The charismatic black mayor of Detroit will today appear before a district court to be arraigned for perjury, obstruction of justice and misconduct in office after becoming embroiled in a sex scandal.

Kwame Kilpatrick is accused of lying on oath that he did not have an affair with Christine Beatty, his former chief of staff at City Hall, and did not exchange confidences with her about a lawsuit.

The charges were brought after a newspaper printed a number of raunchy text messages apparently sent from Mr Kilpatrick's city-issued pager, contradicting statements that the couple had made on oath denying that they had affair in 2002 and 2003.

The 37-year-old Democrat, a former teacher who was dubbed the "Hip-Hop Mayor" because of his youth and energy when he was elected in 2002, last night faced calls to resign from every member of the City Council.

The married father of three has however refused to stand down and has begged not to be condemned until the case against him is heard.

"I look forward to complete exoneration once all the facts have been brought forth," Mr Kilpatrick said yesterday, as he was charged. "I will remain focused on moving this city forward."

He will lose his job automatically if he is convicted of a felony, and could face a 15-year prison sentence on the perjury charge alone.

Ms Beatty, who was married at the time of the alleged affair and has two children, faces similar charges but has made no public comment on them so far.

The saga began several years ago when two police officers filed a lawsuit against Mr Kilpatrick, claiming that they were whistleblowers who had been fired for investigating claims that he used his security unit to cover up his affairs.

Called to give evidence at the trial last August, both the Mayor and Ms Beatty denied that they had ever had a sexual relationship.

But these claims were undermined in January this year when the Detroit Free Press printed extracts from 14,000 text messages, which use flirty and sometimes sexually explicit language to discuss where to meet and how to keep the liaison secret.

"I've been dreaming all day about having you all to myself for 3 days. Relaxing, laughing, talking, sleeping and making love," Mr Kilpatrick reportedly texted to Ms Beatty on October 16 2002.

Kym Worthy, a Wayne County Prosecutor, began her investigation the day after the text messages appeared in print.

Unveiling the charges against Mr Kilpatrick and Ms Beatty yesterday, Ms Worthy issued a stern lecture on the importance of telling the truth.

"Some have suggested that the issues in this case are personal or private," she said.

"Our investigation has clearly shown that public dollars were used, people's lives were ruined, the justice system severely mocked and the public trust trampled on... This case is about as far from being a private matter as one can get."

When he was elected Mr Kilpatrick projected himself as Detroit's great black hope, capable of turning around four decades of decline. The decline of its car making industry has left Detroit one of America's most troubled cities, with high levels of poverty and unemployment and a dwindling population.

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