MANILA, SEPT. 24 -- A series of bombings attributed to military rebels and economic turmoil stemming from the Persian Gulf crisis are feeding a wave of coup jitters here and prompting calls for stronger leadership.

In the latest and most serious of more than 30 bombings in Manila since mid-August, two explosions in luxury hotels in the Makati financial district Sunday injured eight people, including a Japanese businessman and his two children.

Shortly before the blasts, a leader of the military rebels, cashiered army colonel Gregorio Honasan, called Aquino the "root cause" of the country's problems and predicted that her "vindictive, corrupt and incompetent" government would soon be ousted in a "bloodless coup."

Aquino told reporters today that her government is considering "stricter measures" to prevent more bombings, but she ruled out declaring martial law, as her predecessor, president Ferdinand Marcos, did 18 years ago this month. Besides injuring bystanders in some cases, the bombings are "really terrible for our economy insofar as tourists and investors are concerned," Aquino said.

Compounding Aquino's troubles is labor disorder following a nearly 30 percent increase in oil prices Friday. A strike today by a leftist union of "jeepney" passenger-vehicle drivers to protest the increases was generally ineffective, but authorities are bracing for further agitation linked to expected price hikes in other sectors.

The government has been trying to condition the public for fuel price increases since August, when the gulf crisis made them inevitable, pointing out that prices here are still the second-lowest in Asia after Indonesia's. Still, the government remains wary of potential repercussions. Two of the six coup attempts against Aquino in her four years in office have been launched following oil price increases.

Further complicating matters, the New People's Army (NPA), a 19,000-member Communist guerrilla group, today rejected Aquino's Sept. 12 declaration of a unilateral cease-fire by government forces in the capital and several northern provinces that were heavily damaged by a July 16 earthquake. A statement signed by NPA "chief of staff" Romulo Kintanar accused the government of "insincerity and high-handedness" and vowed to "intensify military operations in those quake-damaged areas and in Metro Manila."

Considered the more immediate threat, however, are the military rebels, who authorities say are trying to destabilize the government.

Philippine officials and foreign analysts generally discount the rebels' ability to stage an outright military takeover, but none rules out another try. The rebels are seen as having ample ammunition to keep the government on edge, in light of widespread public frustration over the perceived weakness of Aquino's presidency, uncertain backing for her in the armed forces and mounting economic difficulties.

The uneasiness was illustrated recently when panicky callers jammed military switchboards with reports that rebel paratroopers were descending on Manila's international airport. Government troops rushed to the scene, only to find about 20 unmanned hot-air balloons that had strayed from a town fiesta in the nearby province of Cavite.

Particularly unsettling have been the bombings, which began Aug. 13. Most have caused only minor property damage, but lately the attackers have been growing bolder.

One bomb this month went off inside Manila's Fort Bonifacio, headquarters of the Philippine army, near a building where the army commander was hosting a cocktail party. Earlier, military intelligence agents had foiled a raid on an armory in the capital, arresting four men who tried to drive off with 71 weapons. Military officials identified the leader of the group as a civilian associate of Honasan.

The bombings started about the time that Honasan called for a resumption of "tactical operations" against the government in response to the military's efforts to track down another rebel colonel, Alexander Noble, in the jungles of the southern island of Mindanao.

Noble, who served as deputy commander of Aquino's elite Presidential Security Guard before he joined the most recent coup attempt in December 1989, has eluded capture so far.

Since the December coup attempt, which left more than 100 people dead and nearly toppled Aquino before U.S. warplanes staged a show of force in her support, the ranks of the Presidential Security Guard have been doubled to about 1,500 members. In addition, a secretive new military Counter-Intelligence Command has been created to help detect future rebel moves.

Equipped with its own armored vehicles, helicopters and boats, as well as advanced communications and night-vision equipment, the Presidential Security Guard is considered a formidable obstacle to a new coup attempt, although some of the same morale problems that afflict other units have been reported.

While little is known about the rebels' military organization, some Philippine and foreign analysts now believe that three groups -- Marcos loyalists led by former general Jose Maria Zumel; Honasan's newly renamed Nationalist Revolutionary Alliance, known by its Tagalog initials as RAM; and a shadowy group called the Young Officers' Union, or YOU -- have joined forces under an "executive committee" composed of the groups' leaders.

"What you've got now is the loyalists, the YOU and the RAM grouped in a loose coalition," said a Western source who monitors the Philippine military. "But we don't know how closely they're organized."