TOKYO - Japan's parliament laid the groundwork yesterday for amending the country's pacifist constitution, boosting Prime Minister Shinzo Abe's drive to give the armed forces a larger global role but adding to critics' concerns about a resurgent Japanese militarism.

The country's 1947 constitution was drafted by U.S. occupation officials after World War II, and it has never been amended. Many Japanese credit the charter's pacifist clause, Article 9, with keeping the country out of war since 1945.

Although many more steps are required to change the charter, critics and experts warn that a constitutional change could rattle neighbors with bitter memories of Japanese imperialism in the last century.

"Although Japan doesn't have the intent of becoming a military power, revising the constitution could be seen by neighboring countries as a move toward militarism," said Hiro Katsumata, a defense analyst at Nanyang Technological University in Singapore.

Yesterday, the largely ceremonial upper house of the parliament approved legislation passed last month by the ruling-party-controlled lower house.

The legislation allows the parliament to work on drafts of amendments for three years but bans parliamentary votes on the issue for that period. Then, two-thirds support in the legislature and a majority in a national referendum would be needed to change the charter.

Yesterday's vote gave a needed political victory to Abe, who has championed strengthening military ties with the United States and a more prominent Japanese role in peacekeeping. Abe has also enacted measures to teach patriotism in classrooms and upgrade the Defense Agency to a full ministry for the first time since World War II.

The conservative leader's approval ratings have suffered in recent months. His ruling Liberal Democratic Party faces upper house elections in July.

Abe applauded the vote, saying the next step was to "engage in a calm but wide-ranging debate" about possible revisions.

The constitution bans the use of military force as a means of settling international disputes. Special legislation is currently needed for Japanese soldiers to participate in peacekeeping and other missions abroad.