Philippine troops went on full alert Tuesday after explosions rocked two oil companies on the eve of a general strike called by left-wing unions demanding wage increases.

Military officials ordered 600 soldiers to reinforce the capital's security force of 15,000 and provide escorts to passenger buses not joining the strike. Officials of the left-leaning Labor Advisory Council, which claims a national membership of 3.5 million, announced the Wednesday strike will begin at 5 a.m.The council is demanding a wage increase to compensate for the 29 percent rise in petroleum prices prompted by the Persian Gulf crisis.

President Corazon Aquino, facing a huge budget deficit that has forced her government to resort to massive domestic borrowings and threaten new foreign loans, has refused to grant the increase. Her government also is grappling with a $26 billion foreign debt.

School classes were ordered suspended Wednesday, but government and private companies announced it would be business as usual. Officials said some 200 provincial buses will be fielded in the capital to ferry commuters.

No one has claimed responsibility for the bombings at the Dutch-owned Shell Company in the capital's financial district and the U.S.-owned Caltex Philippines in the tourist area.