The United States welcomed the kingdom of Tonga yesterday as the 49th member of its "coalition of the willing" for the war in Iraq, a club that includes many of the smaller of the 191 member states of the United Nations. The lit is shrouded in mystery, since there are other countries that have agreed to help but refuse to be publicly identified, usually because of domestic or regional opposition to the war. Some of the off-the-record countries have been moved to the public list at their request since an initial roster of about 30 countries was announced March 18, sources said.

The State Department keeps careful track of what dishes each country has agreed to bring to the potluck, but refuses to disclose the contributions publicly because of what one diplomat called "political sensitivities and so on."

Besides the United States, the only countries making substantial military contributions in Iraq are Britain and Australia, and no other countries have been publicly identified as helping finance the war. But the United States hopes more countries will help pay for the reconstruction of post-war Iraq. Some have agreed to provide technical assistance for the rebuilding, and some have given Iraq-earmarked contributions to humanitarian organizations.

Here are the official criteria, as provided by the State Department:

"Each country is contributing in the way most appropriate for it. Some have contributed military combat and support forces to the coalition. Others are providing access, basing and over-flight rights. Still others have committed themselves to post-conflict peacekeeping and reconstruction efforts. Some countries have simply come to us to say that they would like to join the coalition to lend their political voice in support."

Below is the latest list, with examples of the contributions, according to staff and wire reports and administration sources.

-- Mike Allen

Afghanistan -- Issued statement calling for "a united and independent Iraq."

Albania -- Offered use of airspace, land and ports to U.S. military.

Angola -- Was briefly taken off the public list, then restored.

Australia -- Providing naval gunfire support, as well as special forces and fighter aircraft operating in Iraq.

Azerbaijan -- Offered to take part in post-war humanitarian efforts.

Britain -- Co-founder of the coalition; has committed more than 45,000 military personnel, along with planes and ships.

Bulgaria -- Soon will have troops in the region to respond to chemical or biological attacks.

Colombia -- Issued statement of support.

Costa Rica -- Added since list was revealed on March 18; issued statement saying the country is "loyal allies of loyal friends."

Czech Republic -- has troops in the region to respond to chemical or biological attacks.

Denmark -- Submarine is monitoring Iraqi intelligence.

Dominican Republic -- Issued statement of support.

El Salvador -- Providing diplomatic support and post-war reconstruction and demining assistance.

Eritrea -- Issued statement of support.

Estonia -- Offered to help with post-war reconstruction.

Ethiopia -- Added after initial announcement.

Georgia -- Offered its military infrastructure to U.S. troops.

Honduras -- Issued statement of support.

Hungary -- Host of a U.S. base where Iraqi exiles are trained for possible post-war administrative roles.

Iceland -- Agreed to help in reconstruction and humanitarian efforts.

Italy -- A vocal ally of the administration's Iraq policy; offered logistical help and use of military bases and ports.

Japan -- Issued statement of support for President Bush.

Kuwait -- Most U.S. troops and equipment flowed through Kuwait on the way to Iraq, and many are still camped there.

Latvia -- Parliament passed statement of support for U.N. resolution requiring Iraqi disarmament.

Lithuania -- Offered humanitarian assistance, including doctors.

Macedonia -- Issued statement of support.

Marshall Islands -- Added after initial announcement.

Micronesia -- Added after initial announcement.

Mongolia -- Issued statement of support.

Netherlands -- Will help with reconstruction.

Nicaragua -- Issued statement of support.

Palau -- Wrote letter of support; added after initial announcement.

Panama -- Offered statement of support; added after initial announcement.

Philippines -- Provided statement of "political and moral support."

Poland -- Some commandos are helping; agreed to deploy non-combat troops; secured an Iraqi oil platform in the Persian Gulf; has troops in the region to respond to chemical or biological attacks.

Portugal -- Was host to the diplomatic summit before the United States, Britain and Spain withdrew their proposed U.N. Security Council resolution authorizing war in Iraq; made air bases available.

Romania -- Sent non-combat specialists in chemical decontamination, medics, engineers and military police to the region in response to a U.S. request.

Rwanda -- Issued statement of support.

Singapore -- Allowing U.S. aircraft to fly over Singapore and allowing use of its ports by the military.

Slovakia -- Sent non-combat troops trained in decontamination to the region to respond to chemical or biological attacks.

Solomon Islands -- Issued statement of disassociation from coalition but is still on official U.S. list.

South Korea -- Issued statement of support.

Spain -- Introduced U.N. resolution with the United States and Britain; providing logistical and humanitarian support.

Tonga -- The latest addition to the coalition.

Turkey -- Denied basing rights to United States, complicating the war plan, but has opened airspace to U.S. warplanes.

Uganda -- Offered to "assist in any way possible."

Ukraine -- Offered to send chemical warfare and nuclear decontamination experts to the region.

United States -- Leader of the coalition, with about 300,000 troops in the region.

Uzbekistan -- Offered statement of support.