The State Department confirmed that nearly every offer of equipment or expertise from a foreign government since the April 20 oil rig explosion would require the U.S. to reimburse that country.

The offers reveal a hard truth about the United States' international friendships: With the U.S. widely regarded as the world's wealthiest nation, there is a double standard regarding foreign aid after a crisis, especially with offers from relatively poor countries.

U.S. disaster aid is almost always free of charge; other nations expect the U.S. to pay for help.

"These offers are not typically offers of aid," said Lt. Erik Halvorson, a Coast Guard spokesman. "Normally, they are offers to sell resources to BP or the U.S. government."

Only Mexico, with wide swaths of poverty among its population, offered the U.S. anything for free. It said it would give the U.S. government some containment boom. BP separately purchased 13,780 feet of boom and two skimmers from Mexico in early May, according to the State Department.

The stingier countries include: