Troops loyal to Lt. Gen. Prosper Avril guarded the National Palace Thursday with anti-aircraft guns and cannons after he declared a state of emergency to counter the week's second military rebellion.

The order Wednesday by the embattled president, in power for just six months, also included a dusk-to-dawn curfew. Early Thursday, he went on state-run television to appeal to the mutineers to end their uprising.Government forces also stood guard outside the national bank and the telecommunications office, which were briefly occupied by the rebels Wednesday.

Sporadic machine-gun fire and what sounded like exploding grenades could be heard during the night. Radio Soleil, the Roman Catholic station, reported Wednesday that one man was shot to death and three other people were wounded overnight, but the circumstances were unclear.

Several hundred youths marched into downtown Port-au-Prince at midmorning and erected barricades of tires and boxes which they set on fire. Soldiers fired into the air to disperse the crowd.

About 25 rebel soldiers and 200 supporters stood outside a military barracks 200 yards away from the palace, which was guarded by loyal soldiers.

Most stores were closed, and few buses or cars moved through the capital.