A conflict between Kurdish tribesmen and Turkish-speaking Azerbaijanis raged into the third day today despite a cease-fire ultimatum from the government in Tehran and a threat to send Ayatollah Ruhollah Khomeini's Islamic Army to quell the fighting.

The combatants in the town of Naqadeh in northwestern Iran apparently ignored the government's demand that they cease fire by 4 p.m. or face intervention by Army troops. Soldiers from a military garrison in the area were sent to the scene around midday, but there were conflicting reports on whether they actually entered the town. The troops reportedly numbered no more than a few hundred and were believed to have taken up positions outside Naqadeh.

Reports from the scene tonight said the fighting died down after nightfall, but it was unclear whether this was because of any truce agreement.

The reports said tension was rising in neighboring towns between Kurdish and Turkish inhabitants, and that authorities feared that the violence might spread beyond Naqadeh.

Tehran newspapers today said up to 80 people have been killed so far in fierce house-to-house fighting in Naqadeh, a town of mixed Kurdish, Turkish- and Persian-speaking inhabitants in Iran's West Azerbaijan Province.

While the battle in Naqadeh dealt a new setback to Khomeini's efforts to restore order and centralized authority to a country wracked by revolution, the ayatollah extended his influence over the government in Tehran by naming a close aide acting foreign minister.

Dr. Ibrahm Yazdi, the deputy premier for revolutionary affairs, was put in charge of the Foreign Ministry today following the resignation last week of Karim Sanjabi. Prime Minister Mehdi Bazargan technically took over the foreign ministers' portfolio, but the task of running the ministry was assigned to Yazdi.

A former cancer researcher in Texas, Yazdi has become the subject of controversy here because of his behind-the-scenes role as a leading member of Khomeini's entourage. Yazdi's consolidation of personal power-he keeps position as deputy prime minister-appeared likely to aggravate strains between staunch Khomeini supporters and an emerging coalition of Iranian Liberals and leftists, who are feeling increasingly excluded by the government.

At same time, the Tehran government issued a warning to the United States and Mexico that any offer of asylum to the deposed shah, his family and entourage would be considered "an unfriendly act." The government said it has invalidated the Iranian passports of the shah and other members of the royal family who left the country before the February revolution that toppled the monarchy.

In Naqadeh fighting intensified today following two days of battles sparked by shooting during a rally for Kurdish autonomy at a sports stadium.

Battling the predominantly Suni Moslem Kurds of the leftist Iranian wing of the Kurdistan Democratic party in today's fighting were Azerbaijanis of Turkish origin and Persians loyal to the Khomeini revolutionary committees. Both groups are mostly Shiite Moslem and more conservative.

In a message to the people of Naqadeh, Interior Minister Ahmad Sadr Haj-Seyed-Javadi called for an end to the fighting "between brother Moslems." Despite his cease-fire ultimatum and threat to send in troops, however, the government appears to have no alternative capable of restoring order short of talking the warring factions into accepting a truce.