Leaders of Mexico and Central America gathered Wednesday for a summit focused primarily on the relentless violence sweeping the region from the US-backed war on drug trafficking.

The United States says 90 percent of the cocaine shipped there from South America passes through Mexico and Central America.

In Mexico alone some 70,000 people have died in drug-related violence since the government deployed army troops to fight drug cartels.

Central America in the 1980s was ravaged by civil wars, and now finds itself again awash in blood as its serves as a gateway to the north, with penetration from Mexican cartels and grinding poverty that makes lucrative drug trafficking a lure hard to resist.

The violence has mainly affected an area known as the Northern Triangle. It is formed by Honduras, likened to one big airport for clandestine drug flights; Guatemala, penetrated by the most bloodthirsty of the drug cartels, Los Zetas; and El Salvador, which is enjoying a respite after a truce among street gangs.

The summit here in the capital of Costa Rica will be attended by Mexico's new president, Enrique Pena Nieto, Guatemalan President Otto Perez and President Porfirio Diaz of Honduras.

It was not clear if Daniel Ortega of Nicaragua or Ricardo Martinelli of Panama will show up.

Guatemala's Perez has called in recent international forums such as the Davos meeting in Switzerland for a change in strategy, saying the US-backed hardline approach is yielding nothing but dead bodies.

He has suggested legalizing drugs to remove the profit motive.

Pena Nieto has not commented on this idea. But he has promised a new strategy based on better cooperation among countries and more intelligence work, although he has kept army troops deployed in the war on drugs.

The countries at the summit will also discuss how to boost trade.

Trade between Mexico and its smaller neighbours to the south has already quintupled over the past decade to $8.2 billion, according to the Mexican finance ministry.

This will be the Mexican president's first trip outside the country since taking power in December.