U.S. officials have repeatedly pressed Japan in recent weeks to extend the mission. Legislation enabling it expires Nov. 1.
Japanese officials have acknowledged, however, that a bill to extend it is unlikely to gain approval by the Diet - Japan's parliament - before the deadline, and that a gap in Japan's activities is inevitable.
Meeting with the premier in his office Friday, U.S. Ambassador to Japan Thomas Schieffer expressed Washington's desire to see the operation renewed, Fukuda told reporters Friday evening.
"I explained to him that we are now in the process of making new legislation, but there may be a temporary interruption of refueling activities," Fukuda said.
Japan's parliament is in gridlock over a new anti-terrorism bill that would extend the refueling mission in the Indian Ocean for a year. Tokyo dispatched ships to the region in 2001 under an old bill, which has been extended three times but runs out Nov. 1.
A new law submitted Wednesday by the ruling coalition limits the scope of Japan's activities in the region, in hopes of mollifying a resurgent opposition, which argues that the mission involves Tokyo too deeply in military operations in Iraq and Afghanistan.
The bill would limit Japanese ships to refueling and supplying water to ships on anti-terrorism patrols, but does not allow them to refuel vessels involved in military operations, such as attacks.
But opposition bloc has refused to cooperate, threatening to reject the bill in the parliament's upper house, which the bloc controls.
The ruling coalition, which holds the lower chamber, can ultimately overrule an upper house rejection. Parliamentary proceedings are expected to spill into November, however.