Gunmen in Iraq killed two Japanese diplomats in an ambush on their vehicle Saturday, an attack that came with Japan moving closer to sending noncombat troops to the Mideast nation.

Japanese officials said the deaths -- the first Japanese killed in Iraq since the U.S.-led invasion -- would not change the government plan to use its soldiers to aid in the country's reconstruction.

"Japan has a responsibility to provide humanitarian and reconstruction aid in Iraq," Prime Minister Junichiro Koizumi (searchtold reporters. "There is no change to our policy of not giving into terrorism."

Details of the attack were still sketchy, but Foreign Minister Yoriko Kawaguchi said that the vehicle was ambushed near the city of Tikrit (search), where the envoys were to attend an aid conference.

"The two were working day and night for the reconstruction of Iraq," Kawaguchi said at a news conference. "Their deaths are extremely regrettable. I am at a loss for words."

Their driver, whose nationality was not immediately known, was seriously injured, said Foreign Ministry spokesman Jiro Okuyama.

Katsuhiko Oku, 45, headed the cultural affairs section of Japan's embassy in London and had been on assignment in Iraq. Masamori Inoue, 30, was a second secretary at the Baghdad mission.

Kawaguchi said she would dispatch a top aide to Iraq Sunday to investigate the killings.

U.S. Secretary of State Colin Powell (searchtelephoned Kawaguchi to express his sympathy, the Foreign Ministry said. Kawaguchi told him Japan would not waver in its commitment to the campaign against terrorism and the reconstruction of Iraq. She also asked for U.S. help in securing the safety of Japanese officials.

Powell told her he instructed staff in Iraq to fully cooperate with Japan, the ministry said in a statement.

Defense Agency chief Shigeru Ishiba said Friday that a recent fact-finding team indicated conditions are "rather stable" in southern Iraq, where the Japanese government will dispatch the troops.

Koizumi has been a firm supporter of the U.S. invasion of Iraq and has emphasized Japan has a responsibility to help rebuild the country. But he has hesitated to put troops on the group as near-daily attacks on coalition forces have shaken public support for the mission.

His defense chief's comments suggested the government may be satisfied with security conditions in a sector near the southern city of Samawah that Japan has been considering for a deployment that will reportedly involve more than 1,000 soldiers from the nation's Ground Self-Defense Force.

Japanese national media reported that Koizumi's Cabinet may give its approval as early as the coming week for an operation in which ground troops would arrive in Iraq early next year.

Parliament approved the deployment of ground troops in July but only on condition that they serve in "non-combat areas," which Koizumi's opponents argue don't exist in Iraq.

Japanese troops have not set foot in a country at war since World War II (search), and none has died in fighting while on a peacekeeping mission. Its only overseas casualties were two Japanese civilians who were slain while supervising elections in Cambodia in 1993.