LA PAZ, Bolivia (AP) – Bolivia’s president said Saturday the government should take over mines where private owners have not invested sufficiently, taking aim at the industry after clashes between rival bands of miners left at least 16 dead.

The violence began Thursday morning when the independent miners stormed the state-owned Huanuni mine, 180 miles south of La Paz, which holds Bolivia’s richest tin deposits. They were demanding more access to the tin deposits. State-employed miners counterattacked to regain control and the groups exchanged gunshots and threw dynamite, killing at least 16 people and injuring at least 60.

On Friday, Bolivian President Evo Morales replaced his minister of mines and the head of the state mining company.

“Mining concessions where there has not been investment must return to the hands of the Bolivian government,” Morales told Indian coca farmers in the central Chapare region on Saturday. He gave no further details about government plans for undeveloped mining concessions.

Morales nationalized the country’s petroleum reserves on May 1, giving all foreign oil companies six months to negotiate new contracts that cede majority control of their Bolivian operations to the state or leave the country.

Hundreds of miners belonging to independent cooperatives and state-employed miners have fought each other with gunfire and dynamite over access to the Huanuni mine. Hostilities between the miners ended in a tentative truce Friday after the government sent 700 police to control the mountainside where the mine is located.

Presidential spokesman Alex Contreras said both sides agreed to allow humanitarian aid to enter the town of Huanuni.

“We’re only in a truce to give our families a burial,” said Roxana Mercado, a leader of the mining cooperatives. “We haven’t stopped the fight. Now the government will say if it will have a solution.”

Bolivian mines once produced more than 30 percent of the world’s tin. But production came to almost a complete halt following a collapse of the world metal market in 1985, and national mining company Comibol slashed its work force by about 25,000.