LA PAZ, Bolivia - President Carlos Mesa said he would submit his resignation to Congress after 17 months in office, warning that growing protests against Bolivia's oil and gas laws could soon block the country's highways and isolate its main cities.

If lawmakers accept his resignation, Mesa would be the second leader driven from office by popular protests in less than two years in South America's poorest country. In October 2003, Mesa succeeded President Gonzalo Sanchez de Lozada, who resigned in the wake of bloody street protests that took the lives of at least 56 people.

Whether Congress will accept Mesa's resignation is uncertain. As an independent candidate he lacks the backing of a political party, but he has a fair degree of popular support. If he steps down, Senate President Sen. Hormando Vaca Diez would be his constitutional successor.

Mesa's announcement came after Evo Morales, an Indian congressman and leader of the nation's coca leaf growers, announced a nationwide road blockade unless lawmakers pass a law raising the taxes foreign oil companies would pay - a law that Mesa says the international community wouldn't accept.