Leftist Gambian rebels under threat of attack by Senegalese intervention troops threatened today to execute one of the Gambian president's two wives, their children and her father as well as an unknown number of other officials unless the Senegalese soldiers withdraw.

The menace came amid what seemed from radio broadcasts and announcements in neighboring Senegal to be a standoff between Senegalese troops around the Gambian capital of Banjul and rebels who rose up yesterday against President Dawda Jawara during his absence in London for the marriage of Prince Charles.

Kukli Samba Sanyang, an obscure, American-educated, 26-year-old leftist who is leading the rebellion, claimed this evening over rebel-controlled Radio Gambia that he holds as prisoners "the Jawara family and the members of the government." If the Senegalese troops do not withdraw and "if Jawara persists in his attitude, everyone will be killed," Sanyang said, speaking Wolof, a regional language used in Gambia and Senegal.

Jawara was in the Senegalese capital of Dakar, arriving this morning from London where he had been attending the wedding ceremonies, reportedly with his other wife. As a Moslem, Jawara is allowed as many as four wives. The two women alternate going with him on official missions.

It seemed likely from the number of hostages taken and the fact that they have been in the rebels' control since the coup attempt began at 5 a.m. yesterday that Sanyang expected Senegal to intervene on Jawara's side. The two countries, both of which are predominantly Moslem, have close relations, and Senegalese troops were sent to Gambia last year during a reported Libyan effort to destablilize the government.

Although Gambia is a former British colony -- a narrow strip along the two sides of the Gamiba River on the West African bulge -- it is surrounded by the former French colony of Senegal to the north, east and wouth, with the Atlantic Ocean forming its border on the west.

At the time of Senegal's intervention last year, Sanyang's Marxist Gambia Socialist Revolutionary Party and a second leftist group, the Movement for Justice in Africa, were outlawed. The other three parties in Gambia's opposition and Jawara's dominatn Progressive People's Party continued to function normally.

[The rebels broadcasts a call for assistance from the Soviet Union and the African nations of Guinea and Guinea-Bissau, The Associated Press reported from Dakar, and accused the Senegalese soldiers in Gambia of killing innocent civilians.]

A woman who identified herself as Jawara's captured wife, Theilal N'Diaye, came on the radio earlier today to announce that she, her children and father and "all the ministers are being held" by Sanyang and an unknown number of rebels. Besides civilian supporters, Sanyang reportedly has with him about 300 of the country's 900-strong paramilitary Field Force. Gambia has no army.

Additional hostages reported held include the Senegalese charge d'affaires and an executive of the Sene-Gambia Committee, a bilateral trade organization. By late tonight, however, the total number of hostages held by the rebels remained unknown.

Sanyang had already broadcast one threat to begin executing hostages by 5 p.m. if his demands on the withdrawal of Senegalese troops were not met. But there were no reports of any executions.

At a press conference this morning in Dakar, Jawara refused to reveal the number of Senegalese soldiers involved. Diplomatic sources reported sporadic fighting around Banjul with Senegalese troops reportedly encircling the city.

President Abdou Diouf of Senegal ordered the troops into Gambia yesterday afternoon after talking by telephone with Jawara in London, Jawara said. A second group of Senegalese paratroopers reportedly dropped onto rebel hands. It was after the capture of the airport that the Senegalese reportedly moved toward Banjul to link up with the soldiers who had come in yesterday across border check points.

In his broadcast, Sanyang said he is "ready to fight the Senagelese, and too bad if I die."

"Too bad if they then kill my father and mother," he added. "I will have striven for the good of Gambia."

It was unclear tonight how much of the capital was in rebels hands and how much was under the joint control of that part of the Field Force that reportedly remained loyal to Jawara's government and its Senegalese allies. But Jawara's wife mentioned in her broadcast that the rebels hold two downtown Banjul buildings: Government House and State House. And it was clear they held the radio.

At his press conference in Dakar, Jawara expressed confidence that the fighting would be crushed quickly. He said he was still in power and called on the rebels to surrender peacefully. His comments, however, were made before it was known that his wife, an unknown number of their children, his father-in-law, his ministers and others were listed in rebel broadcasts as hostages.