Japan will probably participate in a multinational force to be formed in Iraq under a new U.N. Security Council resolution, despite domestic concerns that taking part might be unconstitutional, government sources said Tuesday.

The government says such participation is constitutional because the resolution is expected to indicate that the tasks of the multinational force include humanitarian and reconstruction assistance that do not entail the use of arms, the sources said.

The resolution is likely to be adopted when the council meets Tuesday.

The Constitution renounces war and the use of military force in settling international disputes, and the government could face an uphill task ensuring that Self-Defense Forces troops do not use arms, even though they will be part of the envisaged multinational force.

The move could take Japan’s security policy into uncharted waters; the SDF’s participation in an international force overseas had been regarded as unconstitutional until recently.

Prime Minister Junichiro Koizumi’s Cabinet is expected to officially endorse the SDF’s participation in the force later this month after examining the resolution, they said.

Koizumi’s close ties with U.S. President George W. Bush have led him to agree to SDF participation in the force, they said.

An announcement that Japan will participate in the multinational force will not immediately affect ongoing operations by the Ground Self-Defense Force troops in the southern Iraqi city of Samawah, a Foreign Ministry official said.

The GSDF troops will continue providing humanitarian and reconstruction assistance, including potable water supply and medical services support.

The Air Self-Defense Force will continue its airborne missions between an airport near Samawah and Kuwait, including the transport of U.S. soldiers and materials for the GSDF.

Cabinet Legislation Bureau chief Osamu Akiyama, the top government legal interpreter, said earlier this month that participation by the SDF in a multinational force in Iraq would be constitutional if it is agreed that some participants can be assigned to duties that do not entail the use of arms.

A government official dismissed concern that SDF troops in the multinational force could face a situation in which they had to use arms at another country’s behest.

Even if SDF troops were to be under the multinational force’s command, they would “have the right to refuse” orders, the official said.

The SDF could maintain its own chain of command, even while participating in the multinational force, he said.

But Katsuya Okada, who heads the opposition Democratic Party of Japan, was skeptical.

“Could it really happen?” he asked. The security situation in Iraq is deteriorating, he said.