President Barack Obama welcomed Japan's decision to join negotiations for a U.S.-led trans-Pacific free-trade agreement, saying the move may mark a major milestone in deepening bilateral economic ties.

"Eliminating the barriers to trade between our two countries could provide an historic opportunity to deepen our economic relationship, as well as strengthen Japan's ties with some of its closest partners in the region," Obama, referring to the Trans-Pacific Partnership, told Prime Minister Yoshihiko Noda during a meeting in Honolulu on Saturday.

Noda said Japan has begun the process of easing import restrictions on U.S. beef imposed over fears of mad cow disease, a senior Japanese official said.