Federal investigators have broadened their probe of D.C. Mayor Anthony A. Williams's chief of staff to include allegations that he coerced government employees to work for the mayor's reelection campaign and provided it with confidential personnel records, say sources familiar with the inquiry.

The new allegations expanded an investigation that began in February with reports that Chief of Staff Kelvin J. Robinson had urged a group of the mayor's political appointees to contribute money to the campaign, despite a federal prohibition against D.C. government employees making financial solicitations.

Those allegations and the new ones both concern possible violations of the Hatch Act, which restricts the political activity of employees of the city and federal governments. Penalties range from 30-day suspensions to termination.

Robinson, 41, did not respond to messages at his office. His attorney, Vandy L. Jamison, said Robinson was cooperating with investigators but declined to comment on the specifics of the allegations, saying, "There's no basis for responding to statements that are anonymous."

They have previously said that those who believed Robinson made a financial solicitation misunderstood his comments.

Tony Bullock, spokesman for Williams (D), declined to comment on the new allegations last week.

The U.S. Office of Special Counsel, which enforces the Hatch Act, has questioned a number of administration officials under oath and is attempting to arrange interviews with others.

The investigation began in February after The Washington Post reported that Robinson had urged more than 200 mayoral appointees at a rally in August to contribute money to the campaign.

Two of the officials, speaking on the condition of anonymity, recalled him saying, "Get out your checkbooks." Numerous others had similar recollections of Robinson's remarks at the meeting.

A major focus of the rally, at the city's old convention center downtown, was to instruct the mayoral appointees about how to abide by the Hatch Act while also supporting the Williams reelection effort in the aftermath of a scandal that cost him a place on the Democratic primary ballot. That summer, the mayor's office sought and received numerous advisory opinions from the Office of Special Counsel on the Hatch Act, and the office also provided training in the law to city government officials.

The Hatch Act prohibits the solicitation of funds and non-monetary contributions, such as volunteering for a campaign. It also prohibits officials from using their governmental authority to seek to alter the outcome of an election.

Current and former administration officials, speaking on the condition of anonymity, said that several mayoral appointees felt pressure from Robinson to volunteer for the campaign or work for it full time as an employee.

Former campaign officials also say that they kept an extensive list of mayoral appointees, including their home addresses, wards, voting precincts, private e-mail addresses, home phone numbers and agencies. The Office of Special Counsel is questioning whether such confidential personnel information came from Robinson, sources say.

The presumptive penalty for a Hatch Act violation is termination. Only a unanimous vote of the three-member Merit Systems Protection Board can lead to a lesser penalty. The minimum under that scenario is a 30-day suspension without pay.

All D.C. government employees are covered by the Hatch Act, with the exception of the mayor, members of the D.C. Council and the register of deeds. Employees of other municipal governments are not generally covered by the Hatch Act, and it remains controversial in D.C. political circles.

Dunbar Senior High teacher Tom Briggs lost his job last April because he ran for the D.C. Council in a partisan election, in violation of the Hatch Act. He was later rehired by the school system, an action that has drawn renewed scrutiny from the Office of Special Counsel. Last month, he asked a federal appeals court to exempt city teachers.

Staff writer Allan Lengel contributed to this report.

Kelvin J. Robinson also is accused of providing the mayor's reelection campaign with confidential personnel records.