San Jose - Costa Rica's Turrialba volcano, last active in the 19th century, erupted on Tuesday, spewing ash and steam and prompting authorities to evacuate a small number of people from its slopes.

The 11,000-foot (3,340-meter) volcano is situated east of the capital San Jose in the remote, lushly forested central highlands of the Central American country.

It had shown increased activity since the weekend, Vanessa Rosales, president of Costa Rica's disaster response commission, told Reuters.

"The area around the volcano is not very populated," Rosales said, while adding that ash from the volcano could reach San Jose if activity were to became more severe.

Authorities evacuated 20 people from its slopes. Thirty more people near Turrialba will be evacuated on Wednesday, Rosales said.

The volcano is not near any major coffee production areas.

Turrialba has been dormant since a 22-year active period that began in 1864, according to Juan Segura, the director of the Costa Rican Volcanology and Seismology Observatory.

Ash from Turrialba's last major eruption in February 1866 fell hundreds of miles (kilometers) away in Nicaragua, according to the observatory.