Government troops moved swiftly today to guard President Abdur Rahman Biswas after he fired the army chief for alleged sedition, but witnesses said soldiers in some provinces continued to show signs of rebellion.

Troops in tanks and armored vehicles circled the presidential palace after Biswas dismissed Lt. Gen. Abu Saleh Mohammad Nasim, whom he accused of trying to stage a revolt. Several hours later, Biswas appeared to be in control, and Dhaka, the capital, was calm. However, pro-government troops blocked highways leading to the capital in a preemptive move against soldiers thought to be loyal to Nasim. Witnesses said troops backing Biswas feared pro-Nasim troops might attempt to march into the city.

Ferry service on the Jamuna River, about 60 miles north of Dhaka, reportedly was suspended. "Rival troops are facing off on either side of the river," one newspaper reporter in the region said.

In the northern town of Bogra the situation was in flux, with troops appearing restless outside their barracks, according to local journalists. "It looks as if they are readying for a major move," said one reporter.

In Dhaka, the daily routine of most citizens appeared to continue as usual, but traffic thinned soon after Biswas announced Nasim's dismissal. Troops in about a half-dozen tanks took up positions to protect the palace, while other tank crews, whose allegiance was not known, moved toward the radio and television stations, witnesses said.

It was not clear why Biswas fired Nasim, but they had clashed over an order issued by the defense ministry -- which is under the president's control -- to retire two senior army commanders. Radio and television carried no reports on today's developments but twice played recordings of the president's speech asking Bangladeshis to stay calm. Biswas said he has named Maj. Gen. Mahbubur Rahman as the new army chief.

Bangladeshis have been hoping that elections scheduled for June 12 will end a political crisis that has largely immobilized the nation in recent weeks. The turmoil was brought to a head in March when labor strikes organized by opposition parties forced prime minister Khaleda Zia to step down. In his speech, Biswas referred to the upcoming elections and urged all citizens to remain calm and vote. CAPTION: Bangladesh's Army Chief, Lt. Gen. Abu Saleh Mohammad Nasim, was accused of plotting a revolt.