Japanese defence minister Toshimi Kitazwa said on Tuesday that May was the deadline for resolving a row over the relocation of a US military base on the southern island of Okinawa which risks fraying ties with Washington.
His comments came hours after US secretary of State Hillary Clinton summoned Japan's ambassador to an unscheduled meeting in Washington, at which media said she urged Tokyo to implement an existing plan reached after years of negotiation.
"We have set May as the cut-off point, but that does not mean we'll be satisfied with doing it by then," a defence ministry spokeswoman quoted Kitazawa as telling reporters in Tokyo. "It means we should do it as soon as possible."
He added that he believed all three ruling coalition parties had the same schedule in mind.
Prime minister Yukio Hatoyama said last week he wanted to spend several more months discussing how best to resolve a dispute over the position of the Futenma air base, but one of his party's tiny coalition partners was reluctant to fix a deadline.
Being seen to mishandle relations with key security ally Washington could damage Hatoyama's voter support ahead of a key upper house election in mid-2010. About 68% of respondents to a poll published in the Mainichi newspaper on Monday said they were concerned about ties with the United States under Hatoyama.
The United States wants to push ahead with a plan to shift the Futenma base to a less crowded part of the island, but many local residents say it should be moved off the island entirely, a view Hatoyama backed during his election campaign.
Ambassador Ichiro Fujisaki told reporters after his unusual meeting with Clinton that she had emphasised the importance of US-Japan relations, but Japanese media said she had pressed for implementation of the current plan.
