In an indirect rebuke to the Reagan administration's policies in Central America, the European Community's 10 leaders said today that they are convinced that the area's problems cannot be solved by military means "but only by a political solution springing from the region itself."

Expressing deep concern at the "widespread misery and bloodshed," the 10 European leaders issued their first joint appeal for a local resolution to the Central American conflict and urged respect for "principles of noninterference and inviolability of frontiers."

They also endorsed the current initiative of the four-nation Contadora Group (Mexico, Panama, Colombia and Venezuela) to launch peace negotiations between governments and guerrilla factions.

At the close of a three-day summit, dominated by disputes about the community's finances, the 10 leaders cited Pope John Paul II's visit to Poland and said, "Only a national reconciliation that takes full account of the Polish people's aspirations" can lead the country out of crisis.

On the Middle East, the European leaders called for the restoration of sovereignty in Lebanon through the "complete and prompt withdrawal of foreign forces" except for peace-keeping troops whose presence is requested by the local government.

They also voiced "very serious concern at the distress" of Palestinian civilians in Lebanon and urged that international relief groups should be allowed to assist them without hindrance.

The declarations on foreign policy issues were approved briskly because the 10 leaders were forced to spend nearly all of their time at the summit haggling over a timetable to resolve a crisis over community finances.

British Prime Minister Margaret Thatcher's demand for a $675 million refund was granted only after arduous negotiations produced a consensus linking the rebate with a detailed agenda to enact community budget reforms by December.

Following the summit, Thatcher praised West German Chancellor Helmut Kohl for his help in brokering a "fair and helpful solution."

In the long debates, Kohl frequenty intervened to mediate serious disagreements between Britain and France, according to officials in both delegations.

West German officials admitted that Kohl was eager to preside over a successful summit to gain positive momentum for his important visit to Moscow in early July.

Britain, arguing that it contributes more toward the community's budget than it receives in benefits, has claimed and received a rebate every year since 1980. One of the main aims of the plan to restructure financing is to make contributions fairer and put an end to the annual haggling with Britain.

In a press conference, Kohl explained that it is crucial to avoid a "constant atmosphere of conflict" within the community at a time when the western alliance will be tested by the challenge of deploying new nuclear missiles later this year if the Geneva arms control talks fail to achieve an agreement.

Concerning the budget compromise that merely prolongs the day of reckoning until the next European summit in Athens in December, Kohl said, "There is no reason for euphoria. For the sake of the community, we all had to give ground."

The strong statement on Central America was instigated by the Dutch government, which has been highly critical of the Reagan administration's actions in Central America.

Central America has become a hot political issue in the Netherlands since the death of four Dutch journalists in El Salvador last year.

Members of other European delegations said they share apprehensions about deepening American involvement with the fighting in El Salvador and Nicaragua.

Only Britain expressed some reservations about the tough wording, but Thatcher decided to go along to reciprocate the key support she received from Dutch Prime Minister Ruud Lubbers during the budget debate.

West German officials hailed the summit as a success for their government, not only because Kohl reinforced his growing stature as a conciliatory figure among European leaders, but also for declarations on Poland and the Madrid Conference on Security and Cooperation in Europe.

Bonn government officials said that if the pope's trip to Poland goes well, they would like to enhance contacts with Gen. Wojciech Jaruzelski's government to encourage a relaxation of martial law and reopen a dialogue with the West.

At the behest of the West Germans, the 10 leaders praised "the timely and important initiative" of Spain's prime minister, Felipe Gonzalez, to find a compromise over the prickly issue of human rights in the East-West conference at Madrid. Bonn wants to see the Madrid documents signed to clear the way for a European disarmament conference later this year that the Kohl government hopes might succeed in defusing the anticipated onslaught of antimissile demonstrations this autumn.

Bonn was also pleased that a solemn declaration on European unity--a ritual reaffirmation of vows to proceed toward a political union in the distant future--was finally signed by the 10 member countries nearly two years after West German Foreign Minister Hans-Dietrich Genscher conceived the idea.