Military officers announced today that they had seized power from the elected government of Prime Minister Prem Tinsulanond, but a loyalist group said that the coup attempt was being resisted, and fighting broke out.

Rival military factions exchanged tank and machine-gun fire in central Bangkok, and NBC bureau chief Neil Davis, 52, an Australian, was killed in the cross fire. NBC soundman William Latch, an American, was wounded seriously and rushed to a hospital.

It was not immediately clear whether there were any casualties among the combatants who clashed outside a radio station controlled by the loyalists.

The battle erupted when the rebel tanks opened up without warning and loyalist soldiers inside the compound of the First Army Region Headquarters replied with automatic weapons fire. But the fighting did not knock the loyalist radio station off the air, and the government later began jamming broadcasts by the rebels.

Only blocks away from the scene of the battle, Thais were going about their business normally and streets were clogged with traffic.

Earlier, tanks and troops of the opposition faction surrounded Government House, where the prime minister has his office. Prem was on a visit to Indonesia.

A statement broadcast by coup leaders said they also were in control of the Supreme Command Headquarters, the Parliament building and the government radio station, Radio Thailand, early this morning. The statement said anyone not obeying the revolutionary party's orders would be "dealt with decisively."

In the announcement broadcast on Radio Thailand, the coup leaders said they were acting in the name of a "revolutionary party" led by retired Gen. Serm Nanakorn, a 65-year-old former Army commander and deputy prime minister in the late 1970s.

The announcement called on troops to remain in their barracks and asked civilians to stay calm. The king and queen of Thailand and all members of the royal family were reported safe.

The radio broadcast cited the economic situation as the main reason for the coup and said that Thailand's foreign policy would remain the same. The statement said coup leaders pledged to protect foreigners and international organizations in Thailand.

In Washington, State Department spokeswoman Anita Stockman said: "Our embassy in Bangkok is monitoring events there closely, but so far the situation is not clear enough for us to make an assessment." She said the embassy and its employes did not appear to be in any immediate danger and that the State Department had received no reports of any injuries to American citizens.

A woman who answered the phone at the Thai Embassy shortly after 1 a.m. said that Ambassador Kasem S. Kasemsri was aware of the coup attempt, but had gone to sleep and would have nothing to say before later this morning.

About two hours after the coup announcement, a loyalist military group broadcasting on a rival radio station called on all troops to return to their quarters and obey only its orders. The deputy Army commander, Gen. Thienchai Sirisamphan, called on the military to remain loyal to Gen. Arthit Kamlang-ek, the supreme commander.

Arthit also was out of the country on a tour of Europe. Both he and prime minister Prem, himself a general, were reportedly making urgent plans to return to Bangkok.

In its announcement, the revolutionary party said it had ordered the dissolution of Parliament and the Cabinet and had suspended the constitution.

It was not immediately clear which faction commanded the loyalty of the majority of Thailand's military forces.

Diplomatic sources said Serm appeared to be a figurehead and that it was not clear who the real instigators of the coup were.

In 1980, young Army officers tried to seize power in a coup but were defeated by Prem. Arthit led loyalist forces that overcame the coup attempt. He then became a rising star in the Thai military and supreme commander three years later. In the April 1980 coup attempt, a high-ranking general also was used as a figurehead leader by the young officers.

News services reported from Bangkok:

Some of the tanks surrounding Government House carried portraits of King Bhumibol Adulyadej, who is in South Thailand with his queen, Sirikit. The monarchy is a revered institution in Thailand and commands universal loyalty.

Serm in his statement said members of the royal family had been taken into "protective custody" for their safety, but this could not be immediately confirmed.

In Jakarta, a grim-faced Prem continued his official schedule, meeting this morning with Indonesian President Suharto.

Prem was scheduled to leave for home on a special Air Force plane at noon after meeting with Suharto, but Thailand's ambassador to Indonesia, Rongpet Sucharitkul, said later the prime minister would wait until the situation had cleared.

In his statement, Serm said the revolutionary party's top priority would be to improve the economy. Tough austerity measures imposed by Prem's coalition government in recent months have sent Thailand's economy into a tailspin.

Late last year Arthit denounced the devaluation of the Thai currency, the baht, and said this had caused concern within the rank and file of the military. But his differences with Prem's coalition government were resolved and his term of service was extended.