CARACAS, Venezuela (AP) _ Border troops killed 14 Venezuelan fishermen at a weekend picnic, mistaking them for Colombian guerrillas, the government said Monday.

Two fishermen escaped the Saturday morning attack by diving into the Arauca River and swimming a half-mile to a ranch near the border town of El Amparo, sources there said.

The Venezuelan-Colombian border incident, the bloodiest in years, took place at Guafitas, 360 miles southwest of Caracas.

Interior Minister Simon Alberto Consalvi said the victims were ''peaceful Venezuelan fishermen,'' not members of Colombia's National Liberation Army as the Defense Ministry originally stated.

''President (Jaime) Lusinchi has ordered a wide, summary investigation into the incident,'' Consalvi told The Associated Press on Monday.

Grimelda de Marquez, an El Amparo government official, said in a telephone interview the fishermen ''carried no weapons at all. At most some had just knives, as any ordinary fishermen do.

''They were going to have a chicken stew when soldiers started to fire. They were all honest people.''

She quoted the two survivors, Jose Hugueto Arias and Vollmer Gregorio Pinilla, as saying the 14 bodies ''were bullet-riddled beyond recognition.''

Other sources in El Amparo, speaking on condition of anonymity, quoted the two as calling the shooting - a land attack supported from the air - a ''slaughter of defenseless, peaceful people who were sailing toward the beach on a weekend picnic.''

Gen. Humberto Camejo Arias, who commands the special border security force, was quoted in press accounts immediately after the killing as saying the group had been armed with light submachine guns, explosives, and grenades, a list of possible kidnap targets, and a map of Venezuelan oil installations in the area.

He was quoted as saying the victims were allegedly members of the National Liberation Army, a leftist Colombian guerrilla group.

Pinilla and Arias were transfered under police custody on Monday from El Amparo to police headquarters in neighboring San Cristobal, 400 miles west of Caracas, and will give testimony in San Cristobal, the sources reported.

Consalvi blamed the shooting on a ''lamentable confusion'' on the part of the troops, who are responsible for guarding the river border against incursions into Venezuela by Colombian guerrillas.

''This is the only explanation we have for now,'' he said.

Earlier Monday, the Defense Ministry said 16 Colombians were killed, but two bodies had yet to be found and 14 were still being identified.

A ministry spokesman said Monday the men were part of a group of about 50 who were crossing the Arauca to enter Venezuela from Colombia.

Venezuela can pump up to 52,000 barrels per day of oil from the area, and last year completed an oil pipeline from Guafitas to a small refinery 90 miles north at San Silvestre.

Venezuela increased its border security in February in response to a rise in kidnappings of its citizens by alleged Colombian guerrillas.