PANAMA CITY, PANAMA, JULY 5 -- President Eric Arturo Delvalle tonight ordered an investigation of charges against military strongman Gen. Manuel Antonio Noriega and called for a dialogue with the opposition, but opposition leaders immediately rejected the initiatives as insufficient.

Delvalle's nationally televised speech was intended as a conciliatory gesture toward opposition forces who have demanded during a month-long crisis that Noriega step down. But it appeared instead to reflect the narrow maneuvering room available to Panama's civilian president, who was put in place in 1985 by Noriega.

Delvalle's predecessor, Nicolas Ardito Barletta, has said that he was forced out by Noriega after demanding an investigation of one of the charges against the general, complicity in the murder of opposition figure Hugo Spadafora. The president's speech appeared to be his final chance to calm Noriega's sharpening confrontation with his middle-class opponents in the face of another week of protests planned by pro- and anti-Noriega forces.

Opposition leaders predicted that the speech would do little to abate the protests. In many Panama City neighborhoods, residents took to the streets immediately afterward to bang pots and honk horns, the hallmark protest of the anti-Noriega forces.

Delvalle said he had instructed Attorney General Carlos Villalaz to investigate accusations that Noriega was involved in assassination and election-tampering, leveled by his former second-in-command, Col. Roberto Diaz Herrera.

However, the opposition, made up largely of middle-class business and professional groups, as well as the Roman Catholic Church, has called for an investigation by an independent, impartial commission. Diaz Herrera, who was forced out of the military June 1, has suggested that Noriega named the attorney general behind the scenes to head the probe.

"At least Noriega should be separated from his post while the investigation goes on," said Ricardo Arias Calderon, head of the opposition Christian Democratic Party. A June 26 resolution by the U.S. Senate also called for Noriega to step aside during the investigation.

Arias Calderon flatly rejected Delvalle's invitation to "sit down formally to talk."

"I'm willing to talk to anyone about when Gen. Noriega will leave, and that's it," Arias Calderon said. "The nation does not want a change of mechanisms. The nation wants a change of regime."

Delvalle's brief speech echoed some opposition complaints. He called for an end to abuses of press freedom, in part a reference to wild and sometimes vulgar stories appearing in three Noriega-controlled newspapers about the general's political enemies. Delvalle said the 20,000-member Panamanian Defense Forces would have to respect civilian authority and withdraw from politics.

But he announced no concrete measures to enforce these recommendations.

Left-wing Noriega supporters seemed likely to be disappointed by the speech as well.

They have been pressing for several business-oriented Cabinet members to be fired and for a stronger government stand against payment of the nation's $4.5 billion foreign debt and against implementation of austerity measures required by international creditors.

Delvalle made no reference to these pressures in his speech.

The statement, awaited since Friday amid much tension, came after a series of peace-making overtures during the weekend from progovernment parties. A turning point came Friday, the day after progovernment, machine-gun-carrying men sacked and burned a department store belonging to Roberto Eisenmann, an exiled opposition newspaper publisher.

Panama is accustomed to peaceful politics, unlike neighbors in Central America engaged in civil wars. The intensity of the current political clash has frightened many Panamanians.

This morning's papers published a communique by legislators from the Democratic Revolutionary Party, the official armed forces party, in effect chastising its left-wing members whose calls last week for "popular violence" against the opposition encouraged the attack on the store.

"We reject violence as a way of settling our differences," the legislators said, calling for a dialogue.

At a meeting Friday night at the home of Archbishop Marcos Gregorio McGrath, three government officials met with three prominent businessmen "to talk sense, not bullets," according to one participant, banker Federico Humbert.

Humbert denied an earlier report that the businessmen had insisted Noriega step down. But he said the talks ended without result.