Guerrillas of the April 19 Movement raided two provincial towns and set off a bomb at Bogota's El Dorado international airport, the Interior Ministry said today.

An estimated 300 guerrillas shot up the police station at the provincal capital of Mocoa, killed the police chief, robbed two banks and kidnapped the assistant mayor, the ministry said.

The guerrillas also killed a bank guard and a boy apparently caught in cross fire during the gun battle between police and the insurgents, ministry spokesman Lorenzo Solano said.

The guerrillas held the city more than two hours, during which they delivered a propoganda speech, then fled into the nearby mountains, official sources said.

It was the largest operation ever carried out by the April 19 Movement, known as M-19, which had previously specialized in urban tactics and publicity-oriented acts such as the 61-day occupation of the Dominican Embassy in Bogota last year.

Mocoa is a town of 50,000 about 75 miles from the border with Ecuador.

In the town of Palestina, another 60 guerrillas shot up the local police station, wounding one policeman, the radio station Caracol said.

Officials said the bomb at the airport exploded in an empty restroom and no one was injured. They said the guerrillas left propaganda leaflets behind.

The M-19 takes its name from the presidential election of April 19, 1970, which was lost by exdictator Gustavo Rojas Pinilla. His youthful leftist followers went underground and emerged in 1974 as the M-19.

Earlier today, the April 19 Movement named three dissident members as responsible for the kidnaping in January and slaying last week of American Bible translator Chester Bitterman.

The communique confirmed for the first time a split within the ranks of the guerrilla movement.