PANAMA CITY, JUNE 9 -- Dramatic accusations leveled at Panamanian military chief Gen. Manuel Antonio Noriega by his former chief of staff gave rise today to violent street demonstrations and crackling tension in this capital city.

For the third day in a row, an opposition newspaper carried detailed allegations by Col. Roberto Diaz Herrera linking Noriega to fraud in the 1984 presidential elections and to the deaths of a former ruler, general Omar Torrijos, and Hugo Spadafora, a critic of Noriega.

It was the first time a high-ranking officer left the closed brotherhood of Panama's allegedly corruption-ridden armed forces to hurl public charges against comrades in arms, and particularly against strongman Noriega, the power behind the government. Diaz was forcibly retired June 1.

About 3,000 rock-throwing demonstrators clashed repeatedly on the capital's main avenues with riot police, known as the Dobermans, armed with clubs and shields. Some protesters were beaten severely, and police fired tear gas and scattered rifle rounds to disperse the crowds.

Diaz's "confession" added a new source of instablity in this nation that hosts the headquarters of the U.S. Southern Command and the strategically vital Panama Canal.

"We've been using the word crisis in this country for years. But this has brought on a more severe state of tension," said Archbishop Marcos McGrath, the leader of the Roman Catholic Church here.

The U.S. Embassy noted the "tremendous impact" of Diaz's statements and added: "The United States strongly supports the efforts of Panamanians to get all the facts out in the open in a manner that is fair to all. Panamanians can only resolve the situation on the basis of the truth."

Since Sunday, Diaz has been holed up in his elegant mansion here, surrounded by followers armed with automatic weapons and Molotov cocktails, and has been giving interviews round-the-clock.

Late today, Diaz agreed to surrender to church representatives the weapons used to guard his house. He said three priests would stay there, protecting him and his family. He issued a confusing statement, saying he was "giving up the struggle" but not retracting his charges.

A church communique called for an independent commission to investigate the charges.

Noriega said yesterday that he would not "enter into polemics," because "the current situation is the result of a conspiracy whose name is known." Captains and majors signed a statement expressing their loyalty to the general. The armed forces spokesman, Maj. Edgardo Lopez, suggested that Diaz was mentally unstable.

Diaz first appeared in the media on Saturday, criticizing a comment by Noriega in Guatemala that he planned to remain as commanding general for at least another five years. He assumed the post in 1983.

On Sunday, the opposition daily La Prensa carried part of a rambling interview with Diaz that began with an announcement that the colonel wished to "get closer to the Lord." Diaz accused Noriega of helping him plot the 1984 election fraud, final details of which were arranged "in my own house."

The 1984 elections were widely believed to have been fraudulent. Nicolas Ardito Barletta briefly became president, until Noriega dethroned him less than a year later. The lack of fair elections has troubled Washington, which seeks a steady government in Panama and has promoted electoral democracy north of here in Central America as part of its strategy against the leftist government in Nicaragua.

Diaz has charged:That Noriega "was directly involved" in the July 31, 1981, death of Torrijos, a popular nationalist, in a crash of a private plane in the jungle. Diaz, a cousin of Torrijos, charged that Noriega arranged for a small bomb to be planted on the plane and that he "sent a message" to Vice President Bush about Torrijos' death.

Diaz, in a later news conference, claimed that Noriega conspired with a U.S. general, the CIA and others to plant a bomb aboard Torrijos' aircraft, The Associated Press reported. Diaz identified the U.S. general as Wallace Nutting, then-commander of the U.S. Southern Command.

In Washington, the Pentagon told the AP that it had not heard of Diaz's accusations and said Nutting headed the Southern Command from 1979-83 and retired last summer. A CIA spokesman told the AP, "We do not engage in assassinations . . . ." That Noriega "organized" the September 1985 assassination of Spadafora, a former health minister who organized a guerrilla brigade that first fought in Nicaragua against the late Anastasio Somoza and later against the Sandinista rule that replaced him. The discovery of Spadafora's beheaded body at the border with Costa Rica shocked the Panamanian public. That Torrijos had received a secret donation of $12 million from the late shah of Iran, Mohammad Reza Pahlevi, who lived here in exile.

Diaz said he made enough money to build his own luxurious home and purchase two others with money he made illegally selling Panamanian visas to Cubans wishing to come through Panama en route to U.S. exile.

Diplomats and newspaper editors said Diaz's statements appeared to be a mixture of truth and extravagant falsehoods aimed at his enemies in the Defense Forces.

Diaz emerged briefly from his house this morning to allege that Noriega was preparing an Israeli-trained commando team to storm his house this evening.

"I know his evil ways," Diaz said. Diaz and Noriega had long been rivals for power within the armed forces. Late last night he showed journalists what he said was an internal military document he claimed showed that he should be the top commander by this time and that Noriega should be retired.