Prime Minister Naoto Kan renewed his commitment on Thursday to open up Japan's market to capitalise on overseas growth and stuck to a June deadline to decide whether to join a U.S.-led free trade initiative. In a foreign policy speech, Kan also reaffirmed the importance of the U.S. military presence in Japan given regional tensions including over North Korea's nuclear programme, while calling for tighter ties with Asian neighbours such as China, as Reuters reported. Kan has come under fire from domestic critics over his handling of territorial rows, including one with Beijing last year after Japan detained a Chinese skipper whose trawler collided with Japanese patrol boats near disputed islands in the East China Sea. Ties with ally Washington frayed under his predecessor due to a dispute over a U.S. Marines' airbase. On trade, Kan said he wanted to press ahead with studies into the Trans-Pacific Partnership (TPP), a U.S.-led free trade initiative. Many Japanese businesses are keen to join the TPP, but powerful farming lobbies have resisted. "When my cabinet was formed last June, I felt it was necessary to restore an energetic Japan and to break a sense of deadlock that has continued for nearly 20 years," he said in the speech. "The key is to open up the country, both in terms of thinking and of the economy."