U.S. crude oil exports reached 288,000 barrels per day (bpd) in May, the highest levels since April 1999, data from the U.S. Energy Information Administration showed on Wednesday.
The increase compares to April figures of 268,000 bpd, data showed.
Exports to Canada hit 263,000 bpd, the highest number on record, data showed, unchanged from volumes in the previous month.
Meanwhile, exports to Spain, the first on record with the EIA, were 17,000 bpd. Traders said the shipments were likely test batches of Canadian crude by Repsol for its Spanish refineries.
Exports of crude to Switzerland increased to 8,000 bpd in May from 5,000 bpd in April.
The U.S. Commerce Department approved 13 crude oil re-export licenses in May. Licenses show approvals to Spain and Switzerland.
The United States does not allow exports of its own oil with few exceptions such as barrels heading to Canada and the re-export of foreign oil. Exports under the exemptions need to be approved by the department's Bureau of Industry and Security.
(Reporting By Catherine Ngai; Editing by Chris Reese, Bernard Orr)