eftist gunmen holding two Cabinet ministers hostage along with more than 85 of this country's business leaders released 15 of their captives tonight as indirect negotiations began with the government.

An initial deadline of this evening for release of about 40 political prisoners -- including a Salvadoran guerrilla leader recently captured in Honduras -- apparently passed without the threatened killing of any hostages.

The 15 freed hostages included women and custodial employes of the Chamber of Commerce building, seized by about a dozen guerrillas during a session last night. A guard was killed and two businessmen injured in the assault.

Some 200 soldiers and police surrounded the one-story structure, moving back to a distance of about 500 yards on demand by the guerrillas. This city of 250,000 is second in size to the capital, Tegucigalpa, 150 miles to the southeast.

As the siege of the building in a normally quiet middle-class suburb continued, it was clear that this once-quiet country surrounded by central America's turmoil has seen a sudden escalation of its own political violence.

Members of a group called the Cinchoneros burst in on the special businessman's meeting addressed by Honduran Treasury Minister Arturo Corleto, Economic Minister Gustavo Alfaro and Central Bank President Gonzalo Carias about 6:30 last night. There reportedly were no U.S. citizens inside at that time, although a few other foreigners were said to be among the captives.

The assailants, who are believed to be allied to the insurgents in neighboring El Salvador, have demanded that Salvadoran guerrilla commander Alejandro Montenegro and about 40 other prisoners be released by Honduran security forces. Three days ago, Honduras acknowledged capturing Montenegro on Aug. 22.

The guerrillas threatened to begin killing hostages if their demands were not met, according to interviews with captives and the occupiers, conducted over the telephone by local reporters.

This and similar revolutionary groups here have been heard from before: machine gunning a car carrying U.S. military advisers in early 1981, leaving two Americans seriously wounded; hijacking a Hondoran airliner in March 1981 and forcing the release of 15 leftist prisoners, including Salvadoran guerrilla leader Facundo Guardado.

Many Hondurans say the Cinchoneros -- who take the name for their "Popular Liberation Movement" from the nickname of a 19th century Honduran peasant leader -- are not Honduran but Salvadoran leftists or Nicaraguan Sandinistas or other "Communist subursives" from outside the country.

Some Honduran officials note that most of the demands made by this and other groups concern not Honduran issues or prisoners but Salvadorans who have been captured through involvement in support networks for Salvadoran rebels.

The United States has sent increasing numbers of military advisers along with aid to this country to bolster its newly democratic government as a stabilizing force in the region -- and help curtail the extensive arms trafficking across its porous borders with Nicaragua and El Salvador.

Honduran security forces under Gen. Gustavo Alvarez meanwhile have cracked down on Honduran dissidents and leftists, more than 60 of whom are said to have "disappeared" last year and were believed by their families to have been imprisioned. In June 1981, Fidel Martinez Rodriguez, the founder of the Cinchonero movement, was reported killed by the government.

But a new, tougher breed of opponent has sprung up. The taking of the Chamber of Commerce here is the boldest move yet against the government.

There was no evidence among the throngs of spectators standing a few hundred yards from the building this afternoon that there was much support for the move.

By early this evening it was no longer possible to talk over the telephone to the hostages or their captors, but Honduran Roman Catholic Bishop Jaime Brufau and Venezualan Charge d'Affaires Hugo Alvarez were going in and out to keep up conversations with the terrorists.

The Cinchoneros had released the wounded businessmen almost immediately last night. One reportedly had a bullet in his lung, the other apparently was hit in the leg when terrorists blasted through the front and back doors of the building with automatic-weapon fire. Another businessman later escaped through a window.

After Brufau and Alvarez concluded a series of talks inside the building, a businessman who had a perforated ulcer, according to the doctor treating him, was carried out on a stretcher by Honduran Red Cross Volunteers. Then six women and eight men walked out, many of them visibly shaken, some in tears and none able to talk at any length before they were hustled away in a bus by government security men. One, a young man identified as Cupertino Fugon, said in response to a question about how he felt, "Good, now that I'm outside."