MOSCOW - The United States and Russia have reached an agreement on "all documents" necessary to sign a new nuclear arms treaty, a senior Kremlin official said Wednesday, and the White House said the two nations are "very close" to signing it. Czech officials announced that Prague will host the signing of the new US-Russian treaty to reduce long-range nuclear weapons that would replace the 1991 Strategic Arms Reduction Treaty. They did not give a date. President Barack Obama spent an hour Wednesday in the White House briefing Democratic Sen. John Kerry, chairman of the Senate Foreign Relations Committee, and Sen. Richard Lugar, the committee's ranking Republican. Both would play major roles in Senate ratification of the emerging treaty. Two senior US officials in Washington said there were still technical issues to resolve in an "annex" to the main treaty, but predicted no hurdles to completing the entire deal within days. They spoke on condition of anonymity due to the sensitive discussions. One official said an announcement that the treaty is complete is expected Friday. White House press secretary Robert Gibbs and the Kremlin official said a final agreement is not likely until Obama and Russian President Dmitry Medvedev speak again, most likely in the coming days. Gibbs said last time they spoke about the treaty was March 13. The Kremlin source, speaking by telephone to The Associated Press, said all the documents, including the treaty, have been agreed upon. Russian Foreign Minister Sergey Lavrov said last week that the treaty was 20 pages long, with an extensive protocol attached. The Russian ambassador to Prague, Alexey Fedotov, told Czech President Vaclav Klaus the date for the signing, which will be released later, Klaus' office said. Prague was the city where Obama committed the United States last April to seeking "a world without nuclear weapons." As part of that strategy, Obama shook hands with Medvedev last summer on plans to reduce sharply both countries' nuclear stockpiles. The two leaders had hoped to enshrine the new limits in a replacement for the 1991 START accord, but that treaty expired in December as the talks dragged on.