LA PAZ, Bolivia — President Morales struggled to assert control over a badly fractured Bolivia yesterday as protesters set fire to a town hall and blockaded highways in opposition-controlled provinces, impeding gasoline and food distribution.

At least 30 people have been killed in the poor Andean nation this week, Interior Minister Alfredo Rada said. All the deaths occurred in Pando province, where Mr. Morales declared martial law on Friday, dispatching troops and accusing government foes of killing his supporters.

Pando’s security chief, Alberto Murakami, told the Associated Press by telephone that 15 people had died and 55 were injured.

The presidency minister, Juan Ramon Quintana, told local radio Red Erbol that authorities had arrested the governor of Pando, Leopoldo Fernandez, “for violating the constitution and generating the bloody killings of the peasants.” Mr. Morales has accused Mr. Fernandez of using Peruvian and Brazilian “assassins” against Morales supporters.

But Pando officials insisted Mr. Fernandez was still free, and Mr. Quintana later clarified on Red Erbol that while the governor “should be put in jail for blatant crimes,” he had not been detained.

Mr. Fernandez did not make any comments yesterday, but he was seen walking through the streets of Pando’s capital, Cobija, where government troops continued to arrive and patrol.

The governor has denied having anything to do with the violence, saying it was not an ambush but rather an armed clash between rival groups.

A presidential spokesman, Ivan Canelas, said without providing details that opposition-led highway blockades continued yesterday and that “an armed group” had set fire to the town hall in Filadelfia, a municipality near Cobija.

“There are people who want to continue sowing pain across the region,” he said.