Former Air Force lieutenant Jerry Rawlings, Ghana's last military ruler, took power once again this morning in a violent, military-supported overthrow of the 2-year-old civilian government he had shepherded into office.

Diplomatic reports reaching Abidjan indicated that there was heavy predawn fighting in downtown Accra, Ghana's capital, and during the early morning daylight hours around the airport.

This afternoon an announcer on Ghanaian national radio stated that "many soldiers have died" without specifying any number. In the same broadcast, which was monitored here, the 34-year-old Rawlings also said ambiguously, "This is not a coup." Well-informed Western and African sources here said it remained unclear what prompted the takeover but it was clear that soldiers were involved on both sides of the fighting.

In a tense voice, reminiscent of the broadcast he made after taking power in June 1979, Rawlings said in a broadcast this morning that he was returning to the anticorruption and populist goals of his earlier coup.

"I am prepared at this moment to face a firing squad if what I try to do for the second time in my life does not meet the approval of Ghanaians," Rawlings announced. If Ghanaians disapprove of his rule, Rawlings added, "you can ask the People's National Party to carry on misruling this country."

In September 1979, after four months as head of state, Rawlings handed over power to an elected National Party government headed by now deposed president Hilla Limann, 47. During his broadcast today Rawlings told Limann to remain in his State House residence. It is not known what has happened to other government officials.

The State Department Thursday night advised U.S. citizens to avoid travel to Ghana. Wire agencies reported an estimate of 1,500 Americans living in Ghana.

In a warning several observers took to be directed at Ghana's largest West African neighbor, Nigeria, Rawlings said that "West Africa would burn" if any country tried to interfere with his new government. Nigeria cut off vital oil shipments to Ghana at the end of June 1979 to pressure Rawlings' first military government to end the execution of leading military officers accused of corruption.

"We are asking for nothing more than proper democracy," Rawlings said in his broadcast. "In other words, the people--the farmers, the police, the soldiers, the workers--as long as you are the guardians, rich and poor, should be a part of the decision-making process of this country and not just something done by a pack of criminals in the" People's National Party, he said.

Rawlings' statement, however, gave no details of the immediate goals of his takeover, the fifth time the military has seized power in Ghana since 1957, when it shed British rule to become the first African colony to achieve independence.

Rawlings' action underlines the sharp reversal of a trend toward political liberalization in West Africa in recent years with the military overthrow of elected governments in Upper Volta, Guinea-Bissau and Liberia.

Rawlings first won notice when he unsuccessfully tried to seize power in mid-May 1979 from the military government of Gen. Frederick Akuffo. During the public trial that followed, Rawlings gained widespread popularity among Ghana's low-ranking soldiers and civilians by stating from the defendant's stand that he sought a return to the honest government of the past.

Inspired by Rawlings' example, on June 4, 1979, a group of middle- and low-ranking noncommissioned officers carried out a second coup and freed Rawlings. Within weeks, eight high-ranking active and retired military officers, including three former heads of state, were executed and dozens of other officials jailed on corruption charges.

There followed four months of "moral revolution" during which numerous military officers were convicted by secret "people's courts." Merchants were punished for hoarding by public caning. Bureaucrats and businessmen were imprisoned on charges of participating in the corruption.

When Rawlings turned over the government to Limann, a politically unknown career diplomat, the young lieutenant publicly warned the new president that the armed forces would not tolerate any more corruption. Corruption and gross mismanagement had been blamed for Ghana's tottering economic situation at the time of Rawlings' 1979 coup. The economic situation continued to deteriorate under Limann.

Limann and his officials, fearful of Rawlings' enduring popularity, clumsily retired him from the armed forces--Rawlings reportedly heard about it on his car radio.

Yet Rawlings' popularity continued to soar--as did the rate of inflation. Ghanaians talked nostalgically of Rawlings' brief reign and the nine-year rule of the country's first leader, Kwame Nkrumah, as the two periods when they were able to afford enough to eat.

"This is a very fragile, frightened government that is always looking over its shoulder at Rawlings," said a Western observer in Accra last year. Rawlings "is a catalyst for all the economic misery here," said another source.