Bush administration officials said Friday the United States will not take part in next week's review conference in Nairobi on the international convention on anti-personnel landmines. But they said the United States shares "common cause" with those seeking to protect innocent civilians from the landmine scourge.

Officials here say the United States is not a party to the 1997 landmine convention signed in Ottawa, and that even sending an observer delegation to the Nairobi meeting would have required it, under U.N. rules, to underwrite a fifth of the cost of the meeting.

But they say the United States applauds the initiative of those who are taking part in the review conference opening Monday, and is committed to working with them to speed progress toward ending harm to civilians caused by persistent mines.

Though the United States is by far the largest sponsor of worldwide mine-clearing operations, it has been at odds with many countries including key European allies over its landmine policy and refusal to join the Ottawa convention.

The convention bans the use, stockpile, production and transfer of anti-personnel landmines but not the larger mines that target tanks and other vehicles.

With U.S. military commanders reluctant to give up the defensive use of anti-personnel mines, the Clinton administration refused to sign the Ottawa treaty but set a target of 2006 for renouncing their use.

In a controversial revision of U.S. policy in February, the Bush administration said it would ban mines without self-destruct features after 2010, but impose no limits on so-called "smart" mines which have timing devices to automatically de-fuse explosives within hours or days.

In a talk with reporters here, Assistant Secretary Lincoln Bloomfield, head of the State Department's Bureau of Political-Military Affairs, said the United States wants to send a "message of partnership" to the Nairobi participants despite policy differences over the Ottawa convention's terms.

Defending the administration's retention of the self-deactivating mines, he said the weapons are useful only in wartime circumstances and are not a hazard to innocent civilians after the conflict is over.

"It's not to say that U.S. military commanders favor the use of this weapon, but to take it out of their arsenal without any other currently-available mechanism to perform that same tactical function could put our forces at risk, or could put allied forces at risk, or could risk danger to the population that we're trying to protect," he said.  "I think the President accommodated a sensible requirement of the military without compromising humanitarian principles, because these munitions that have self-destruct and self-deactivate features have not been the ones that caused the crisis."

Mr. Bloomfield said Bush administration policy is aimed at dealing with the "totality" of the global landmine problem and that it is pressing for a 50 percent increase, to $70 million, in mine-clearing assistance in fiscal 2005.

Officials here say U.S. aid is going to 30 countries, though the biggest programs are in Iraq, Afghanistan, Angola, Cambodia, Laos and Vietnam.

They say total U.S. mine-clearing aid since 1993 has been nearly $1 billion, and has been a major factor in an estimated 50 percent decline in civilian casualties from the mid-1990s, when some 25,000 people a year were being killed or injured each year by mine detonations.

About three-quarters of the world's countries have signed the Ottawa treaty but more than 50 have not, including major military powers Russia, China, Indian and Pakistan in addition to the United States.

A written statement released here urged the more than 140 countries that will take part in the Nairobi meeting to increase funding for mine clearing, to ban the sale of all persistent mines including anti-vehicle devices, and to eliminate mostly-plastic non-detectable mines, which pose a special threat to mine-clearing teams.