Trade ministers convened here by the General Agreement on Tariffs and Trade met around the clock today in a last-ditch bid to resolve agricultural trade differences between the United States and the European Economic Community.

But U.S. spokesmen at the conference said that while there had been "some movement" on some of the issues at stake, "there has been no movement at all on agriculture."

The ministers, who have been negotiating since Wednesday on a five-point pledge to keep world trade channels open, set a deadline of midday tomorrow to reach agreement. GATT officials expressed doubt that any agreement on the five-point package could be reached by the deadline set.

The issue that has plagued the talks since the outset is a U.S. demand that GATT undertake a study aimed at phasing out subsidies used by the EEC to promote exports of farm goods such as grains, butter and poultry.

The United States maintains that these subsidies have helped European exporters obtain more than equitable shares of world markets.

Yesterday, the Danish president of the EEC's Council of Ministers, Uffe Ellemann-Jensen, said the U.S. demand was not simply a plea for freer trade in Middle Eastern or Eastern European markets, but a bid to destroy the entire EEC agricultural policy.

"We will accept studies of all problems, including agricultural subsidies," Ellemann-Jensen said. "We will not accept any measures that jeopardize the essential interests of our people."

Amid delegates' charges of U.S. "arm twisting" on the farm subsidies issue, U.S. conferees -- led by Trade Representative William E. Brock -- have been said to heighten tensions with claims that the United States will let loose a flood of farm surpluses on world markets, unless the Europeans agree to phase out their subsidy program.

These threats were underscored by statements from some U.S. congressmen attending the conference. Sens. Robert Dole (R-Kans.), John Danforth (R-Mo.) and Jesse Helms (R-N.C.) were among those present.

On Thursday, a ranking U.S. trade official at the conference said the United States is prepared to dump dairy products and perhaps grain onto world markets in retaliation for European foot-dragging on the subsidies issue.

The official said the first retaliatory step would be to dump dairy products, especially butter, onto the world market. He claimed there were ready markets for U.S. salted butter surpluses in the Middle East, North Africa, South America and Eastern Europe.

However, U.S. Deputy Secretary of Agriculture Richard Lyng, who is also a member of the U.S. delegation to the conference, said the most likely markets for the dairy surplus were the Soviet Union and its Eastern bloc allies.

Sir Roy Denman, head of the EEC's delegation in Washington, said today that if the U.S. follows through on its threat to dump surpluses on world markets, the EEC would charge it with violation of its obligations under the GATT and demand compensation.

The chairman of the conference, Canadian Foreign Minister Allan J. MacEachen, has formed an eight-member "crisis group" to find language that might accommodate the agricultural subsidies dispute and find solutions to the other issues before the conference.

MacEachen said today "some progress" had been made on these issues, which include commitment to a general "ceasefire" on protectionist measures; a GATT study on the feasibility of free trade in services such as insurance and banking; tighter restrictions on trade "safeguards," such as quotas to curb imports, and a more efficient and binding way to settle disputes between trading partners.

However, MacEachen stressed that without a settlement on agriculture, movement on the other issues was endangered. "Everything depends on getting all the elements of the final package to hang together", he said.

A good portion of the delegates have said that whatever emerges from the deliberations, the meeting can hardly be called a success. "The simple fact that there was an argument at all, despite twelve months of preparation, shows that a piece of paper alone will not be enough to resolve the problems", one diplomat said. CAPTION: Chart, U.S. FOREIGN TRADE, by Gail McCrory -- The Washington Post; Picture, The U.S. trade deficit widened by $5.3 billion in October, assuring a record trade deficit for this year of more than $42 billion, according to the Commerce Department. Photo by James M. Thresher