The United States on Tuesday defended safeguard emergency import restriction measures to protect domestic steelmakers and voiced readiness to take similar action in other sectors if necessary.

In an annual trade policy report, the Office of the U.S. Trade Representative also urged Japan to accelerate deregulation while welcoming Prime Minister Junichiro Koizumi's reform initiatives.

Despite strong criticism from Washington's trading partners against high tariffs on steel imports to rescue the ailing U.S. steel industry, the USTR stressed the legitimacy of such safeguard measures.

"We will continue our commitment to the effective use of statutory safeguards, consistent with WTO (World Trade Organization) rules, to assist American producers," U.S. Trade Representative Robert Zoellick said in the report submitted to Congress.