Japanese ground troops have left for Iraq - marking the country's first full military deployment to a combat zone since World War II. The humanitarian mission has drawn strong criticism in Japan, where many people fear the troops could come under attack.

About 90 Japanese soldiers were given an emotional send-off Tuesday as they prepared to leave for a controversial humanitarian mission in Iraq. They comprise the first detachment of about 600 ground troops to be deployed there by the end of next month. Japan has already sent several advance teams to the area to monitor security.

The troops left by bus from their garrison on the northern island of Hokkaido, with relatives, military veterans and soldiers lining a road inside the base and waving Japanese flags. Relatives wore yellow ribbons, symbolizing their hope to see the troops return safely. The troops will fly to Kuwait for training and will then go on to the Iraqi city of Samawah.

Once they arrive in the war-torn nation, they will purify water and rebuild public facilities. The troops will have no combat role, since the Japanese constitution outlaws them from taking part in international conflicts. However, in accordance with new legislation, they will carry weapons and defend themselves if attacked.

Japanese Defense Agency Chief Shigeru Ishiba pledged Tuesday that he will try to keep the troops safe. He says so far plans for the deployment are proceeding smoothly and that he is confident that the troops will meet the high expectations of Japan and Iraq. He adds that the government is taking all possible measures to protect the troops.

But concerns are widespread in Japan that insurgents will attack the troops or that terrorists will target Tokyo - as they promised to do if Japan joined the U.S. led effort to rebuild Iraq. For these reasons, opposition lawmakers have boycotted votes in Parliament to formally approve the dispatch. But the ruling coalition still managed to get a bill passed in Parliament's powerful lower house.

U.S. Deputy Secretary of State Richard Armitage, in Tokyo for strategy talks with Japanese officials, on Monday praised Japan for joining the 63-nation-strong reconstruction effort, and said the people of Samawah were eagerly awaiting the Japanese ground forces.

"These are people who ultimately want what we all want: to put food on the table and put children in school without living in fear," says Mr. Armitage. "So it is understandable that their enthusiasm arises not just from the benefit the self-defense forces will bring to the security but from the constructive touch for which Japan is rightly famous."

Japan has firmly supported the U.S. led war in Iraq and has pledged five billion dollars to help finance the rebuilding effort. Prime Minister Junichiro Koizumi says that Japanese troops are needed to help secure Iraq, underscore Japan's alliance with the United States and ensure the flow of Middle Eastern oil to energy-poor Japan.