Tanzanian jets early today bombed Uganda's international airport at Entebbe in a fresh escalation of the war against President Idi Amin and his Libyan allies, according to diplomats here.

Soviet-built Mig21s damaged the main runway-which has been under Tanzanian 122mm artillery fire for the past four days-in what Tanzanian sources say was retaliation for a raid by a Libyan Air Force Tupoley 22 bomber on the Tanzanian city of Mwanza.

Sources in the Tanzanian captial of Dar es Salaam said the raid was successful and that all Tanzzanian aircraft had returned to base, presumably at Mwana, on the shores of Lake Victoria.

No Ugandan or Libyan aircraft were believed on the ground at Entebbe, which was officially closed to commercial traffic a week ago. Tanzanian artillery was credited with damaging a Uganda Airlines Boeing 727 at Entebbe Staurday.

Diplomats noted that the new raid marked anothe rmilestone in Tanzania's gradual admission of its military presence inside Ugandan exile forces trying to oust Amin.

Sources in Dar es Salaam explained the more forthright Tanzanian position-which stopped short of officially announcing the Entebbe raid-by saying Libya's massive entry into the war had escalated the conflict.

Both the Mwanza and Tentebbe raids appeared to have achieved more psychological impact than material damage. Tanzanian government sources said that one man was wounded-and six gazelles from a nearby animal sanctuary killed-in the Mwanza raid which missed camouflaged Migs and fuel storage tanks.

Entabbe Airport has been largely abandoned by Amin's forces in favor of Nakasongola and Gulu air bases north of Kampala.

Libyan airliners, however, have landed at Entebbe at night without lights, presumably to bring in Libyan reinforcements. And Friday a Uganda Airline flight flew from Entebbe to Nairobi.