Leaders of 18 nations in eastern and southern Africa appealed Saturday for increased external aid after warnings that the Persian Gulf crisis could derail development in the region.

Ending a two-day summit meeting of the Preferential Trade Area (PTA) covering 190 million people, they said only regional cooperation could help halt Africa's economic decline.But they added in a statement that huge foreign assistance was needed to help bolster development programs.

The PTA was born out of the Lagos plan of action agreed at a summit of the Organization of African Unity (OAU) in 1980. It started operating three years later and aims at a free-trade area and a unified currency by the year 2000.

It is made up of Angola, Burundi, the Comoros, Malawi, Mozambique, Zambia, Zimbabwe, Rwanda, Kenya, Uganda, Mauritius, Tanzania, Ethiopia, Sudan, Somalia, Swaziland, Lesotho and Djibouti.

The OAU chairman, Ugandan President Yoweri Museveni, warned at Friday's opening that continuation of the four-month gulf crisis threatened disaster for economic development in Africa.

Rocketing fuel prices were sucking dry scarce foreign exchange reserves.

The summit appealed to the U.N. Food and Agriculture Organization for urgent financial and technical help to halt pests and diseases threatening forests and crops.

The leaders signed several PTA instruments covering multilateral industrial enterprises and institutions, a customs bond guarantee agreement and a PTA reinsurance company, but concrete achievements from the summit were sparse.