WASHINGTON —  The co-chairmen of the nonpartisan presidential debate commission told representatives for President Bush and Sen. John Kerry (search) on Wednesday that they must act immediately to finalize details for the debates, the first scheduled in just over two weeks.

The Kerry campaign agreed last month to the commission's proposal for venues, dates and moderators for three debates involving the presidential candidates and one for the vice presidential candidates. However, the Bush campaign has not said whether it will agree to the proposals.

The Commission on Presidential Debates (search) could meet at any time this week but must convene by Monday, co-chairmen Frank J. Fahrenkopf Jr. and Paul G. Kirk Jr. wrote in a letter. The commissioners said the schools hosting the debates, law enforcement agencies, television networks and others need at least 10 days for planning details.

"The four universities, their surrounding communities and their state governments have incurred significant costs in preparing for the four debates. They cannot wait any longer for confirmation that these historic events will go forward as planned," the commissioners wrote to Bush debate negotiator James A. Baker III and Kerry negotiator Vernon E. Jordan.

The Bush campaign did not return a call seeking comment on the letter. A Kerry campaign spokeswoman, Christine Anderson, said Wednesday, "We expect things to be moving forward in the coming days."

The commission proposal calls for presidential debates Sept. 30 at the University of Miami in Coral Gables, Fla.; Oct. 8 at Washington University in St. Louis; and Oct. 13 at Arizona State University in Tempe, Ariz. The vice presidential debate is scheduled for Oct. 5 at Case Western Reserve University in Cleveland.