Washington (CNN) -- Talks between Russia and the United States on a new arms-control agreement are "almost at the finish line," a State Department official said Wednesday.
Discussions between the two sides continue on technical details but a deal is "really close," said State Department spokesman Mark Toner. "I would describe it as steady progress toward the end goal," he said. "We are extremely close but I'm not going to characterize a deal on that."
The agreement would replace the Strategic Arms Reduction Treaty (START) arms-control agreement between the United States and Russia, which expired in December 2009.
President Barack Obama hopes to talk to Russian President Dmitry Medvedev about the deal in the "next several days," White House press secretary Robert Gibbs said Wednesday.
The Czech government has agreed to host the signing of a new arms-control agreement between Russia and the United States in Prague once it is complete, a Czech Foreign Ministry spokesman told CNN.
The United States made the request, said Filip Kanda, the spokesman. He pointed out that negotiations on a new agreement continue in Geneva, Switzerland.
"It is too early to say what the date will be," he told CNN.
Gibbs said Wednesday that the administration had always considered returning to Prague -- where Obama presented his vision for a world free of nuclear weapons last year -- for the signing. But "there are still something that need to be worked out," he said.
The new arms agreement would reduce the number of deployed strategic warheads each side can have. The United States currently has approximately 2,200 strategic warheads deployed; Russia has an estimated 2,500. Under the new agreement each side would be allowed between 1,500 and 1,675 nuclear warheads, officials have said.
The treaty also would limit the number of "delivery vehicles," the strategic bombers and missiles that carry the warheads, to between 500 and 1,100 for each side, officials have said. The current limit is 1,600 but the United States actually has 900 delivery vehicles; Russia has an estimated 600.
For the American side, Obama will have the final word on the precise numbers within the agreed-upon parameters.
Sen. John Kerry, D-Massachusetts, who met with Obama at the White House on Wednesday to discuss the START negotiations, said the president expressed confidence that "real progress is being made."
"I assured the president that we strongly support his efforts, and that if the final negotiations and all that follows go smoothly, we will work to ensure that the Senate can act on the treaty this year," said Kerry, who is chairman of the Senate Foreign Relations Committee, in a written statement.
Republican Sen. Richard Lugar, R-Indiana, also attended the meeting.
CNN's Jill Dougherty and Charley Keyes contributed to this report