Senior U.S., European and Japanese diplomats met here again yesterday in an accelerated effort to negotiate a new East-West trade policy, and diplomatic sources said afterward that progress has been made although agreement may not yet be imminent.

European diplomats continued to express optimism that the Reagan administration might soften or drop its controversial sanctions against development of the Soviet natural gas pipeline to Western Europe in return for agreement on an allied policy on trade with the Soviet Union.

"There is progress being made. People who were being difficult are not so much now," one diplomat said in an apparent reference to France, which previously had been portrayed by U.S. officials as blocking agreement.

Another diplomat indicated that a unified European-Japanese position on a compromise proposal is expected to be studied by U.S. officials over the weekend. There were unconfirmed reports that another meeting may be held Monday.

A Reagan administration spokesman said after yesterday's talks that the "character of the meeting was not one to make a breakthrough and it didn't. It hasn't jelled and it still could not jell. I suppose there is progress in that they are still talking, but nobody is betting on it."

British Ambassador Oliver Wright told reporters as he left the State Department last night, after two more hours of talks, that "we have reached no conclusions."

Against the backdrop of intense diplomatic maneuvering, Democratic National Chairman Charles T. Manatt charged yesterday that the Reagan administration is using the negotiations with the allies "as a political pawn to make an announcement before Tuesday's elections."

Manatt charged that the administration had brought pressure against Japan and France to agree to a compromise approach on a substitute for the pipeline sanctions policy, threatening difficulties on other trade issues if they do not.

"These delicate matters affecting the employment of thousands of American citizens and U.S. relations should not be used for partisan political purposes," Manatt said.

Presidential spokesman Larry Speakes, traveling with Reagan on a campaign swing through the West, quickly characterized Manatt's charges as "bunk." He added, "We do not anticipate any immediate change in the president's position on the pipeline. There have been consultations and they will continue."

Another White House official said, "No, despite what Manatt says, I don't see anything on the horizon."

A State Department official said of the pace of the talks, "Nobody is slowing it down and nobody is artificially speeding it up. It's going as fast as it can."

A spokesman for the Japanese Embassy stressed that the sanctions issue had not been raised by the United States "in the usual sense of linkage."

"In the sense that the trade sanctions issue is another thorny problem, just as it is with Europe, then it is an issue, like citrus, beef or others. But in no way is there linkage, as if to say, 'you do this, we do that,' " said embassy spokesman Hiroshi Ota.

Sources familiar with U.S.-French trade relations also said they had detected nothing to back up Manatt's charge of U.S. pressure on Paris.

During a campaign swing a week ago through areas in the Midwest hard hit by layoffs resulting from his sanctions policy, Reagan had spoken in optimistic terms about the negotiations then under way in Washington on a formula for East-West trade.

The administration sanctions policy, designed as a response to the imposition of martial law in Poland, has turned into one of the most divisive issues between the United States and its major allies in years, threatening the cohesion of the Atlantic Alliance.

Secretary of State George P. Shultz began to move shortly after he succeeded Alexander M. Haig Jr. to find a formula to replace the sanctions. This effort, along with the administration's Middle East peace proposal, has turned into a major challenge of Shultz's abilities to achieve solutions to complex issues.

The United States is seeking broad agreement with members of the European Economic Community, Canada and Japan on a policy for trade with the Soviet Union covering credits, energy purchases, sale of high-technology items and general levels of trade in strategic goods.

One proposed outline for an agreement is believed to include a commitment to launch an intensive study of these issues, along with agricultural sales to the Soviets, that would produce a unified NATO alliance policy that could be joined by the Japanese.

During the course of the study, there would be a moratorium on energy purchases from the Soviet Union and sales of high-technology items to Moscow. This would allow the United States to lift or sharply modify its pipeline sanctions policy.

The London-based Financial Times reported in its Thursday editions that France has moved within the past week to suspend imports of Soviet crude oil and energy products because of a serious imbalance in trade between the two countries.

Trade Minister Michel Jobert said last week that France's agreement with the Soviet Union on the importing of Siberian gas could be jeopardized if Moscow did not take steps to improve the trade balance.

The meeting yesterday between Undersecretary of State Lawrence S. Eagleburger and ambassadors from several European countries and Japan was the second in a week and followed talks among the Europeans in Luxembourg on Tuesday.

The latest round of discussions is an expansion of earlier talks between Eagleburger and the ambassadors from Britain, France, West Germany and Italy, the four countries now directly affected by the pipeline sanctions.

The negotiations are an outgrowth of a general agreement among NATO foreign ministers at a meeting in Canada in early September to reach a consensus on the difficult issue of trade with the East Bloc.

Sources familiar with the course of the negotiations noted yesterday that the recent addition of the Common Market to the discussions could provide a framework for European countries to join in an overall agreement that they might otherwise find politically difficult in isolation.

At the same time, it also makes a quick agreement less likely, since any language that is agreed upon in Washington still would have to pass back through a meeting in Brussels and approval by individual countries.