Gas stations in Madrid and the northeastern Catalonia region began running out of fuel Monday as an indefinite strike by truckers began to bite.

The protest over soaring fuel costs began at midnight Sunday.

Antonio Onieva, president of Madrid's station owners organization, told reporters that by 5:30 p.m., 15 percent of the capital's outlets had run out of fuel. Manuel Amado, president of Catalonia's owners' federation, said 40 percent of Catalonia's 1,714 stations had sold out.

The stoppage led to lengthy lines at many gasoline stations across the country as drivers rushed to fill up.

Truckers also blocked a number of roads around the country, including some leading into the center of Barcelona and the international border with France.

"We are the ones who move the goods that this country needs to keep working. If we stop because we haven't got the money to buy fuel then the country will stop," Julio Villascusa, president of the transport association Fenadismer, told Cadena SER radio.

Fenadismer said more than 90,000 drivers have been called to take part in the strike.

The strike was not expected to have a major effect on city food markets until later in the week.

There was almost no movement of trucks early Monday at Mercamadrid, the main wholesale food market for the Spanish capital.

Development Ministry transport chief Juan Miguel Sanchez said the government will guarantee market supplies.

Fenadismer representatives and Development Ministry officials met Monday morning for four hours and were meeting again in the early evening.

A strike by fishermen across Spain also protesting fuel costs has entered a second week. News reports said smaller boats that fish closer to the coast had now joined the protest, which began May 30.