The Defense Department has recommended to President George W. Bush the use of tactical nuclear weapons as a military option to retaliate for last week's terrorist attacks in the United States, diplomatic sources said Tuesday.

It is unknown whether Bush has made any decision. Military analysts said the president is unlikely to opt for the use of nuclear weapons because doing so would generate a backlash from the international community and could even trigger revenge from the enemy involving weapons of mass destruction.

However, the Pentagon's suggestion shows the determination of U.S. officials to retaliate for the first massive terrorist attacks on the U.S. mainland, the analysts said.

The recommendation appears intended to deter terrorists, they said.