LIMA, Peru (AP) _ A series of strong earthquakes jarred the ancient Incan capital of Cuzco Saturday, killing at least five people and injuring 50, the municipal government reported.

It said two adults and three childrens were crushed when the walls of their adobe homes on the outskirts of the city crumbled.

Cuzco, 350 miles southeast of Lima, has been crowded with tourists because of its vantange point for viewing Halley's comet, the city government said, but it had no reports of any foreigners being among the quake victims.

People fled into the streets as the quakes shattered window, cracked walls, broke water pipes and cut off electricity in some areas.

City officials said five quakes and aftershocks struck Cuzco between 3:30 p.m. and 7 p.m.

The Peruvian Geophysical Institute said the strongest quake registered 5 on the Richter scale and its epicenter was 12 miles northwest of Cuzco, which is in a valley of the Andes Mountains and has a population of about 200,000.

A police spokesman in Cuzco told The Associated Press in a telephone interview that during one of the tremors a section of one of the towers of the Roman Catholic cathedral fell into the street. The cathedral is on Cuzco's central plaza.

Mauro Carrasco, a telex operator in the Cuzco municipal building told AP, ''There was panic. Most people have left their homes and gone into the plazas and the outskirts with their blankets because the tremors are continuing.''

Police reported most of the injured were being treated for cuts from broken glass and injuries from fallen masonry.

Radio Programas, a privately owned Lima radio station, said its Cuzco correspondent reported the quakes caused a side of a mountain to break lose in an outlying district of Cuzco province but there was no report of casualties.

Peru's most distrastrous earthquake occurred in 1970, killing more than 65,000 people in several Andean towns. One town, Yungay, and all of its 20,000 inhabitants were buried when the quake set off a landslide.

Celestino Miranda, a spokesman for Cuzco's luxurious Hotel Picoaga, said many of the foreign guests were frightened by the quake, but none was injured.

He said the tremors did not damage the hotel, which is located in the center of the city.

The Richter scale is a gauge of the energy released by an earthquake as registered on a seismograph. Every increase by one number means the ground motion is 10 times greater.

A quake registering 5 is capable of causing considerable damage, while one at 6 could cause severe damage and a 7 magintude represents a major quake.