According to Associated Press reports, officials said traffic was blocked at two points, but truckers left narrow corridors in other places, slowing down other vehicles.
The truckers are demanding a 50 percent cut in fuel taxes, which now range from 30 to 60 percent, and an increase in rates. The government offered only a gradual 20 reduction over the next three years in the current road tolls.
The truckers' union president, Hector Moya, said 6,270 vehicles were parked at a dozen points in the Pan-American Highway, while the government reported that 900 truckers were taking part in the blockade, AP reported.
The government has admitted the strike will cause serious economic damage, especially if exports are affected.
AP reports said the truckers' strike has no deadline.