Colombia's Nevado del Huila volcano erupted in a shower of hot ash, prompting authorities to evacuate thousands of people and declare a state of alert.

There were no reports of damage or injuries.

The volcano, 150 miles southwest of Bogata, erupted at 11:08 p.m. Monday (0508 GMT Tuesday), according to the Colombian Institute of Geology and Mining.

Martha Calvache, deputy director of the institute's seismic department, told Caracol Radio that authorities were unable to estimate the size of the eruption.

She said the volcano was expelling ash. "Other types of material could come, like lava, but we don't at the moment know the exact situation," she said.

Caracol Radio reported that between 13,000 and 15,000 people who live near the volcano were being evacuated.