FILE PHOTO - Containers from Hamburg Sud Shipping Company are seen at La Guaira port, in La Guaira, Venezuela March 31, 2016. REUTERS/Marco Bello

CARACAS (Reuters) - Two major shipping lines this month have raised their rates for transporting goods from the United States to Venezuela, according to three industry sources and two documents, as U.S. sanctions limit transit between the two nations.

Washington on May 15 banned direct flights between the United States and Venezuela, citing safety concerns, as part of a broad package of sanctions meant to pressure Nicolas Maduro into resigning as president of the crisis-stricken country.

Citizens and social service organizations often depend on air and sea shipments for basic food and medicine in the hyperinflationary nation where a monthly minimum-wage salary barely pays for a single meal.

Shipping lines Hamburg Sud and King Ocean Services have added a surcharge of $1,200 per container of cargo that leaves the United States for Venezuela after May 15, according to documents seen by Reuters. That service has in recent months been costing between $3,000 and $5,000, depending on the cargo, according to two sources at local ports.

“Shipping companies have increased the cost of their services because of the risk involved in coming to Venezuela with sanctions,” said a local shipping industry source who asked not to be identified.

Hamburg Sud and King Ocean Services did not respond to requests for comment.

In 2016, shipping lines were charging up to three times more to travel to Venezuela than to other South American countries, according to fee schedules seen by Reuters at the time.

U.S. sanctions do not prevent shipping lines from delivering goods to Venezuela.

Washington in April sanctioned four shipping companies and nine oil tankers it said were involved in oil shipments to Cuba.