The election of Barack Obama as U.S. president has given crucial impetus toward implementing the Comprehensive Nuclear Test Ban Treaty more than a decade after it was negotiated, according to test ban officials.

In a major policy address yesterday, U.S. Defense Secretary Robert Gates laid out a stark choice for the nation between testing the existing nuclear arsenal or modernizing it with new weapons if the United States is to retain a safe, secure and reliable nuclear deterrent.

The top U.S. nuclear weapons commander, Gen. Kevin Chilton, warned today that the nation should not rule out the possibility of resuming explosive nuclear testing to ensure the reliability of the U.S. strategic arsenal.

US military aircraft and monitoring centers scrambled yesterday to determine the size and type of the weapon that North Korea detonated in what is believed to be the reclusive regime's first test of a nuclear bomb.

Russian diplomats believe it is now "highly probable" that North Korea will officially join the nuclear club by carrying out its first underground test of an atomic device.

An effort to develop cooperative seismic monitoring of the Indian Ocean to prevent a repeat of last year's Tsunami is being held up by Indian concerns that the data could reveal too much about their nuclear weapons testing program.

The U.S. Senate has increased funding for the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO) which will boost the existing international network of nuclear monitoring devices (IMS).

White House and Pentagon officials have been closely monitoring a stream of satellite photographs of North Korea that appear to show rapid, extensive preparations for a nuclear weapons test, including the construction of an official reviewing stand, presumably for President Kim Jong Il.

U.S. officials are increasingly concerned that North Korea may be preparing its first test of a nuclear weapon, though they warn that the information is sketchy and not definitive.

Linton F. Brooks, the director of the U.S. nuclear weapons programs, has proposed that Congress approve funds to study the feasibility of building a new, more reliable nuclear warhead that could be deployed without nuclear testing in less than 10 years.