Mexico's mining industry virtually shut down Wednesday when thousands of miners went on strike to support their union boss, who may be ousted amid accusations he responded poorly to a mining tragedy that left 65 coal miners dead.

Mexico's Mining and Metal workers union asked their 250,000 members to halt work indefinitely in coal, steel, copper and other mines throughout Mexico, in support of union president Napoleon Gomez Urrutia. Striking miners also are demanding better working conditions.

The full extent of the strike wasn't clear Wednesday, although a number of major companies confirmed work stoppages — including Penoles, the world's biggest silver producer.

The mining tragedy has turned into a finger-pointing scandal with the miners union embroiled in an internal power struggle and federal and state government officials accusing each other of using the disaster for political gain.

In a statement, the union denied its officials had signed documents supporting a leadership change, and it accused labor authorities of interfering in the union's business.

Gomez Urrutia, who took over the helm from his late father in 2002, is being challenged by Elias Morales, a union dissident who now claims to be the new leader.

Gomez Urrutia's leadership came under fire by relatives of the 65 coal miners who were killed Feb. 19 in an underground gas explosion. The union leader waited more than a week after the tragedy before visiting the Pasta de Conchos mine, 85 miles southwest of Eagle Pass, Texas.

When he came Tuesday, he had to rush into the mining company's offices to escape the angry families confronting him, according to the Mexico City newspaper Reforma.

On Tuesday, unionized workers went on strike at Mexico's two largest copper mines — Cananea and La Caridad — as well as at Grupo Mexico's zinc refinery in San Luis Potosi and its zinc mine in Zacatecas state. The union cited demands for improved maintenance in calling the walkouts at Grupo Mexico, which owns the mine where the miners died.

The walkout also affected coal mining and steel maker Altos Hornos de Mexico, and the Mexican unit of Netherlands-based Mittal, Mexico's biggest steel maker with annual capacity of 3.8 million tons of steel slab, located in the Pacific port of Lazaro Cardenas.

Mexican media quoted Labor Minister Francisco Salazar as saying all the strikes are illegal except for those at San Luis Potosi and Zacatecas, where the union is negotiating contract revisions.

Penoles spokesman Luis Rey said the company has asked the union to stagger the work stoppages so that the company can meet its customer deliveries.

Grupo Mexico has promised 12 miners who survived the blast $9,500 in compensation. Relatives of those killed will get about $75,000 and scholarships so that the miners' children can go to college.

Efforts to recover the bodies were expected to resume by the weekend if the gas levels have dropped, officials said.