Washington ? Moving to widen its hunt for terrorists and cut off their weapons routes at sea, the Bush administration is negotiating agreements with dozens of nations for new powers to police the world’s waters, defense officials said.

The plan being developed, which hasn’t yet been approved by the Pentagon, builds on the months-old ship interdiction operation started largely to capture al-Qaida members fleeing Afghanistan across international waters, four officials said on condition of anonymity.

It envisions giving U.S. forces rights to chase down and board vessels not only in international waters but in another nation’s sovereign waters in some circumstances such as when pursuing ships believed to be carrying al-Qaida or other terrorists whose organizations have global reach. Ships thought to be carrying terrorist weapons or other contraband used to finance them could also be boarded, two of the officials said.

The State Department has been seeking this permission in negotiations with dozens of countries over recent months, two others said, declining to name the countries.

The planning to improve and refine maritime efforts comes as the military looks for more innovative ways to press the war on terrorism including, possibly, more covert commando missions now that al-Qaida has largely been crippled in Afghanistan.

The idea of widening the scope of ship interdictions started in the Arabian Sea in November is the largest and latest piece of a wide effort by a number of U.S. government agencies to get more control over the vast and poorly documented movement legal and illegal of people and commerce on ships, officials said.

In another maritime effort, the U.S. Customs Service has since March negotiated permission to station its inspectors to screen U.S.-bound cargo containers at major ports in Canada, France, Belgium, Singapore and elsewhere.

Roughly 6 million cargo containers enter U.S. seaports annually. Officials said the Sept. 11 attacks on America heightened fears terrorists would use containers to smuggle themselves or nuclear or other weapons into the country.

Another maritime effort started long before the Sept. 11 attacks is being re-emphasized, two officials said. It is aimed at stopping the smuggling of oil out of Iraq, whose trade is restricted by U.N. sanctions imposed after its 1990 invasion of Kuwait.

The interdiction program on terrorism began in late November in the region around Afghanistan as the U.S.-led forces took city after city away from former Taliban rulers. Officials feared Osama bin Laden and other al-Qaida leaders might flee the landlocked country, crossing Pakistan or Iran to the sea. Also, intelligence officials worried about information that bin Laden owned or controlled two dozen ships he might be using to smuggle drugs or diamonds or otherwise funnel money to terrorist activities.

Weeks later, that hunt was expanded to search the Mediterranean for weapons or other terrorism-related cargo.

Over the months, more than 100 ships from allies, including Australia, Britain, Italy, Germany and Japan, have taken part in the operation, which also monitors movement in the Red Sea, the Persian Gulf and waters around Africa.

Naval forces have announced the capture of only four suspects all coming from Iran last month and the sinking of one vessel carrying hashish. But the operation has netted a wealth of documents identifying who is going where and how they are shipping contraband, as well as a greater knowledge about piracy and other activities on the seas, officials said.