Legislation to increase federal gasoline mileage standards suffered a stunning blow in the Senate, forcing proponents to shelve the bill until next year's congressional session.

After unexpectedly losing a key test vote, Sen. Richard Bryan, D-Nev., prime sponsor of the bill, said Tuesday he would give up efforts to push the bill through the Senate this year."We will be back next year," Bryan said in a statement. "We will be back to deal with improving automobile fuel economy because the automobile is where the oil is consumed."

"The truth is simple: To reduce our dependence on foreign oil, we must improve our automobile fuel economy," Bryan said.

In a crucial procedural vote, Bryan failed to get the 60 votes needed to limit debate, handing opponents a victory in their efforts to block the measure. With only a few weeks left before Congress adjourns for the fall campaign, the defeat sealed the bill's fate for this year.

The vote was surprising since Bryan handily won a similar procedural vote last week. Strong lobbying against the bill by automakers and the Bush administration appeared to have turned the tide.

The bill would have raised the fuel efficiency standards for new cars to a fleetwide average of 40.1 mpg by 2001, up from the current 27.5 mpg.

The struggle in the Senate came as the Environmental Protection Agency released its annual gasoline mileage ratings for new cars that showed small foreign-built cars - most from Japan - are the fuel efficiency champs again.