CASABLANCA -- Moslem heads of state, wrapping up a summit in Morocco on Thursday, threatened economic measures against countries that help the Serbs in Bosnia.


A special statement on Bosnia, the issue which has dominated the three-day summit, said: "We express our condemnation of all direct or indirect assistance to the Serb aggressors and we resolve to reconsider present economic relations between our countries and those which support the Serb position."


The statement, echoing a resolution by foreign ministers, said the 52 members of the Organization of the Islamic Conference considered null and void the United Nations ban on supplying arms to the mainly Moslem government of Bosnia.


The foreign ministers had added that their governments would act on this understanding -- an implicit threat to defy the UN embargo -- but the summit statement did not include this.


The leaders charged a working group of foreign ministers "to meet the needs of the Bosnians to enable them to defend themselves" and offered to replace any contingents which pull out of the UN peacekeeping force in the former Yugoslavia.


The heads of state said they would increase humanitarian and economic aid to the Bosnian Moslems through a Bosnian aid fund, the statement said. Each member would contribute between $300,000 and $5 million.


On themes other than Bosnia, a spokesman confirmed that two Arab countries -- Jordan and Iraq -- had expressed reservations on two controversial resolutions passed by the foreign ministers and endorsed by the heads of state Thursday.


Jordan was unhappy that the conference failed to mention its role as patron of Moslem holy places in Jerusalem, and Iraq did not like resolutions which insisted it comply with all UN resolutions relevant to its disputes with Kuwait.


Another theme of the conference was the attempt by Arab governments faced by Moslem militant opponents to fight back through theological arguments and international cooperation.


King Hassan of Morocco, the conference host, suggested they set up an Islamic equivalent of the Vatican to define orthodox doctrine and counter fundamentalist "heresies."


The idea, which would have been a radical departure from Sunni Moslem practice for more than 1,000 years, did not feature in the final statements. but the conference did file the king's speech away as an official document.


The heads of state also approved a code of conduct for combating political violence, mainly by Moslem militants.