ROME, OCT. 28 -- Leaders of the 12 European Community countries moved further along the road to political and economic union today by committing themselves to creation of a European Central Bank in 1994.

Despite the objections of British Prime Minister Margaret Thatcher, the EC leaders agreed on a timetable to accelerate the transfer of national sovereignty after a single market is achieved in the next two years. In a joint statement, they also vowed to align their foreign and security policies "to strengthen the identity of the community and the coherence of its actions on the international scene."

The leaders said a common European currency could be introduced by the end of the decade. They promised in the meantime to enhance the legislative powers of the European Parliament, create a European citizenship and reach more decisions by majority vote to create momentum toward an eventual political union.

The final blueprint for political and economic union is to be approved by the 12 leaders at a special intergovernmental meeting in Rome on Dec. 14.

The new European Central Bank, which would work with central banks from member states, would operate independently and be responsible for maintaining stable prices throughout the community. But it would only assume its sovereign powers in the final phase -- 1997 at the earliest -- when exchange rates would be irrevocably fixed and the European Currency Unit, the ECU, would be established.

Thatcher denounced the notion of setting a date for the next phase of monetary union, contending that all necessary decisions should be taken on a new move before a date is determined to launch it. But the other leaders again refused to let her opposition block them from moving ahead with plans to cede more power from national to European decision-making councils.

French President Francois Mitterrand, while spurning the notion of a "two-speed Europe," said that it was important to try to persuade more reluctant nations such as Britain to proceed faster. But such efforts "must not be allowed to slow down all the others," he said.

Thatcher, in turn, accused Mitterrand of hypocrisy in rejecting a common European position in global trade talks that would trim farm subsidies by 30 percent. "Some regard Europe as a protectionist trading group," Thatcher said. "It is France, and not Britain, that has stopped us from putting forward new proposals because it will not accept the present positions of the community or the United States."

France and Germany say that steep cuts in farm subsidies would endanger the livelihood of many of their farmers. The United States has warned that a trade war could break out unless the EC makes a reasonable offer to reduce subsidies. Negotiations on the matter under the auspices of the General Agreement on Tariffs and Trade, called the Uruguay Round, have been underway since 1986 and are scheduled to conclude in December.

European Community trade and farm ministers will try to forge a common position by winning French and German acceptance at another meeting this week. U.S. and community officials say that besides French recalcitrance about the fate of their politically powerful farmers, Chancellor Helmut Kohl also wants to avoid any step that could offend the German agriculture lobby before national elections Dec. 2.

The leaders also postponed any decision on establishing a permanent site for the European Parliament.