The "Fire Volcano" is located in a sparsely populated rural zone between the western, coastal states of Colima and Jalisco, about 300 miles from Mexico City.

Emergency authorities said the explosions have continued since activity started with small blasts on Wednesday, but that the situation was still not serious enough to move the roughly 100 residents of the tiny villages around it.

"The explosions are continuing and a lot of material is coming out, but we do not yet consider it a risk situation," Colima's chief of civil protection, Melchor Urzua, said.

Experts say the activity has been caused by pressure building under a dome that covers Colima's crater. Smoke and gas are now spewing from a crack in the dome.

In a statement, Colima's Volcano Observatory said it hoped the lava flows would continue, relieving pressure inside the cone-shaped mountain.

Villagers were last evacuated in May 2002, after a series of small eruptions. The last major explosion of the Volcano of Fire was in 1913, but it has erupted intermittently in the last decade.

(Reporting by Bernardo de Niz in La Yerbabuena and Frank Jack Daniel and Miguel Angel Gutierrez in Mexico City)