Bianca Jagger and an aide to Rep. Ronald Dellums (D-Calif.) as well as several representatives of relief and church organizations were reported today to have witnessed an incursion by the Salvadoran Army into Honduras near a refugee camp.

Earlier in the day, a plane belonging to the French relief group Aviation Sans Frontieres was set on fire in La Virtud, site of the refugee camp, by a rightist paramilitary group before it could take off to pick up a group of journalists waiting in Tegucigalpa, the capital of Honduras.

The rightist group is presumed to be the Honduran Movement for Anticommunist Action, which painted red graffiti last night on the houses used by the various relief agencies operating in La Virtud.

Approximately 120 armed civilians entered the camp at La Virtud at about noon and surrounded the refugees, officials of Aviation Sans Frontieres said. The officials were in radio contact at the time with the visiting church and relief delegation, which was making a one-day visit to the camp. The group of Salvadoran soldiers remained outside the camp, the officials of the French relief organization said the delegation reported.

Jagger, the Nicaraguan ex-wife of rock star Mick Jagger, and the other visitors took photographs as the civilians tied up about 20 refugees at gunpoint and tried to lead them away, the aid officials said. A discussion ensued between the members of the relief delegation and the armed civilians after which the captured refugees were released and some of the delegation members' cameras were broken by the armed civilians, the aid officials said.

The soldiers and the armed civilians subsequently withdrew to the outskirts of the tiny mountain village where approximately 10,000 refugees live.

Groups of armed Salvadoran civilians frequently operate jointly with Salvadoran troops inside the country.

The visiting delegation -- also including Robert Brauer, Dellums' aide; James Gittings, editor of the Protestant Church publication AD; and Russell Davenport, a consultant to the international relief organization OXFAM -- has decided to stay on in La Virtud, several members told the officials here, to guarantee the safety of the refugees.

The visitors have been in contact with the offices of the United Nations High Commissioner for Refugees from whose offices the two-way radio, often used by the private relief organizations, operates. The U.N. High Commissioner's office has requested an interview with the commander of the Honduran Army in charge of the La Virtud region, officials of Aviation Sans Frontieres said.

The burning of the plane in La Virtud, prevented a group of journalists to join the delegation in a visit to the Honduran camp.

Approximately 10,000 Salvadoran refugees are housed in 10 camps and many peasant homes along the Honduran border.

The refugees, victims of the Salvadoran civil war, are cared for by an assortment of international relief organizations.