Indonesia's most volatile volcano erupted Tuesday after scientists warned that pressure building beneath its dome could trigger the most powerful explosion in years. At least 18 people were killed, including a two-month-old baby, according to doctors and media reports.

Smoke poured out of Mount Merapi, obscuring its cone, according to footage from the private station, Metro TV. Police and volunteers were shown carrying ash-covered corpses, some wrapped in blankets and yellow body bags, to waiting vehicles.

Thousands of villagers started streaming off the 9,737-foot- (2,968-meter-) high mountain as darkness fell Tuesday, crowding into makeshift emergency shelters with straw sleeping mats and bags of clothes and food.

Earlier, many had refused to budge, saying they wanted to tend to crops along volcano's fertile slopes and protect their homes against looters.

While there are fears the current activity could foreshadow a much more destructive explosion in the coming weeks or months, Gede Swantika, a government vulcanologist, said the mountain appeared to be releasing some pressure building up beneath the lava dome.