Widespread revulsion in Africa at the executions of Liberian leaders last month failed to deter the new military leaders there from maintaining political and economic ties with its three neighboring countries.

The successful campaign by the leaders of the April 12 coup in cementing ties with Guinea, Sierra Leone and the Ivory Coast came as Libya reportedly moved quickly to establish close relations in Monrovia.

According to a well-informed source, Libyan leader Muammar Quaddafi sent a special envoy to meet with Liberia's new ruler, Sgt. Samuel K. Doe. The source of the report arrived here recently from Monrovia.

Qaddafi has tried for years to create a "revolutionary" Islamic, pan-African movement.Some observers speculate that Qaddafi, with Libya's oil wealth, will try to become a major influence in economically troubled Liberia. The country, largely Christian, has a Moslem minority estimated at 10 to 20 percent of the 1.8 million population.

The Liberian diplomatic campaign was launched immediately after its delegation was refused permission to land its aircraft in Nigeria to attend the Organization of African Unity economic summit on April 25. The snub came three days after 13 leaders of the toppled civilian government of president William R. Tolbert were executed. Tolbert was executed April 12 by a band of noncommissioned officers in a bid to wrest control of the country from descendants of the freed American slaves who settled the country in the 19th century. The coup put the country in the hand of indigenous Africans.

Deposed vice president Bennie D. Warner, in a confusing series of press statements here and in Houston, Tex., publicly called for African states to "isolate" the new government. But the government's campaign, which diplomatic observers said has been a success so far, has seemingly thwarted any movement to diplomatically isolate the ruling military People's Redemption Council.

African governments generally follow the universal diplomatic practice that emphasizes recognition of states rather than governments. Any strong effort to isolate Liberia's new government would have also been viewed as interference in the country's domestic politics, a sensitive issue in Africa.

Relations between the new government and the United States, which for historic reasons has traditionally maintained close ties with Liberia, soured since the executions. The United States is taking "a wait-and-see approach" in future relations, an informed source said.

If the United States remains aloof, Liberia's military rulers can be expected to turn to other sources of development aid, such as Libya, and significantly alter Liberia's relationship with the United States.

Meanwhile, Liberia's past influence in African councils will be considerably weakened as the continent's leaders deal cautiously with the government that killed Tolbert while he was chairman of the Organization of African Unity. With Liberia's loss of leverage, the United States loses an important ally who often sided with the American foreign policy objectives in Africa.

The new government recently suffered a public setback when the African Development Bank canceled its executive conference scheduled for Monrovia this month. Instead, the bank, which provides development funds to African countries, will hold the conference here in June. One bank source said bank officials, who were in Monrovia planning the conference at the time of the coup, "feel the situation there is too insecure."

The new government was widely criticized following the executions of officials -- all Americo-Liberians or descendants of the American slaves -- on charges of corruption and suppression of civil rights. It was immediately after the executions that Nigeria refused to allow Liberian Foreign Minister Gabriel Baccus Matthews to land.

A Nigerian statement said the participation of a Liberian delegation "may" prove difficult. The statement was apparently alluding to OAU delegates' anger at the death of Tolbert and the execution of former foreign minister C. Cecil Dennis, who was popular with African officials.

It is unclear whether Nigeria, black Africa's most powerful country, will maintain a tough line toward the Liberian military government, but it has kept its diplomatic mission in Monrovia open.

After being rejected in Lagos, Matthews returned to Monrovia and then flew the following day to Conakry, Guinea, to meet President Ahmed Sekou Toure. The two men held three hours of talks and it is understood that Toure expressed his displeasure at the executions. Three days later, Doe announced there would be no more executions.

After the announcement by Doe, who is chairman of the ruling Redemption Council, Matthews and the council cochairman, Maj. Gen. Thomas Weh Syen, flew here with a diplomatic mission. The delegation met with President Felix Houphouet-Boigny and then flew to Sierra Leone to a meeting with President Siaka Stevens.

An official Liberian news report said that Houphouet-Boigny and Stevens promised to continue close ties with Liberia but asked the new government to exercise restraint "in meting out punishment" to about 100 persons still to be tried on charges of corruption.

"The two leaders also revealed," the statement said, "that they had on several occasions urged the late president Tolbert to enable greater participation of the masses in the political process of Liberia, but their appeals went unheeded."

In a bizarre sequence of events, former vice president Warner, who was appointed by Tolbert in 1977, flew here last week and told a press conference on June 30 he was organizing an opposition movement to overthrow the government. Two days later, in Houston, Warner, a Methodist bishop, publicly denied he was in Abidjan and claimed that the news conference had been held by an imposter.

Warner, who was in the United States at the time of the coup, claimed he never left.

Then, last Friday, Warner admitted that he had held the press conference here. He added that he had changed his mind about forming an opposition movement since Doe announced an end to the executions.