The United States said Wednesday it was moving forward with Japan on a long-stalled deal over a military base but declined to say if an announcement would be ready for a summit next week.

Japanese officials have said that a plan to announce an agreement on Wednesday was postponed, following a complaint by three senators who questioned if the emerging deal on Okinawa island made fiscal and strategic sense.

“Let me say that we have made progress in these negotiations” with Japan, State Department spokeswoman Victoria Nuland told reporters.

But she said that Congress “has to be happy” with the effects on the agreement, particularly on the budgetary implications.

“I’m not prepared to predict right now when we’ll go public with where we are. But everybody has their internal procedures, and we’re working through those now,” she said.

The two governments had hoped to seal an agreement in time for the visit of Japanese Prime Minister Yoshihiko Noda to Washington on Monday.

Okinawa has been a longtime source of friction between the Pacific allies as the subtropical island is home to around half of the 47,000 US troops in Japan, who are stationed under a post-World War II security treaty.

Under a 2006 plan, the United States would relocate the Futenma base — a particular point of grievance as it lies in a crowded urban area — to a quiet seashore and move 8,000 Marines from Okinawa to the US territory of Guam.

But a number of activists want to remove the base completely from Okinawa, setting off a political row that led to the downfall of a Japanese prime minister in 2010.

President Barack Obama’s administration wants to press ahead with the new base, likely with the Marines heading to Guam as well as Hawaii and Australia.

But three senators — Carl Levin and John McCain, the top Democrat and Republican on the Senate Armed Services Committee, as well as Jim Webb, an active voice on Asia policy — warned that Congress must give its nod first.

“It is our position that any announcement on this critical matter that goes beyond an agreement in principle at this time would be premature and could have the unintended consequences of creating more difficulties for our important alliance,” they wrote in a letter to Defense Secretary Leon Panetta.

The senators voiced concern about the lack of firm estimates on costs, logistical requirements and environmental studies for the plan.