The move has sparked renewed concerns from domestic and international groups calling for arms control who fear the meeting may pave the way for the United States to move toward resuming its suspended nuclear weapons tests.

U.S. President George W. Bush's administration has been working to boost the nuclear weapons capacity of the U.S., starting research on mini-nukes and shortening the preparation period for conducting nuclear tests with an eye to resuming them.

In the upcoming meeting, a total of 150 people are expected to gather at a U.S. Air Force base in Nebraska, according to the sources, who were briefed about it by the Department of Defense.

STRATCOM, which acts as the command and control center for U.S. strategic forces, is headquartered in Nebraska.

Among those attending are nuclear experts and officials from STRATCOM, the Department of Defense, the Department of Energy -- which holds jurisdiction over the development and management of nuclear weapons -- and the National Nuclear Security Administration, which is involved in research into and testing of nuclear weapons.

The Department of Defense and other concerned government bodies say the meeting aims to discuss the entire U.S. nuke policy.

In what analysts say is a sign the Bush administration is moving toward resumption of nuclear tests, a senior defense official wrote a memo last October which expressed doubts over the prolonged freeze on nuclear tests and identified what it said were the flaws of a program in which nuclear tests are not conducted.

In the memo directed to council members, Edward Aldridge, a defense undersecretary for acquisition, technology and logistics and chairman of the Nuclear Weapons Council, also proposed a meeting of experts to discuss the need to develop new nuclear weapons and the benefits of resumed nuclear tests.

The council is a consultative body on U.S. nuke policy.

Acting upon this, a preparatory meeting was held in January, in which participants decided to discuss the need for nuclear tests, the political consequences of resuming tests, and the connection with missile defense and conventional arms, the sources said.

The participants are also expected to discuss the reduction of about 4,000 nuclear warheads agreed between the U.S. and Russia in the Treaty of Moscow signed in May last year, according to the sources.