Washington, Jan. 30 -- US President Donald Trump on Thursday signed an executive order warning of fresh tariffs against countries supplying oil to Cuba, stepping up economic pressure on the communist island nation.

According to the order issued by the White House, "An additional ad valorem (estimated value) duty may be imposed on imports of goods that are products of a foreign country that directly or indirectly sells or otherwise provides any oil to Cuba."

Issued under the International Emergency Economic Powers Act, the directive labels the Cuban government an "extraordinary threat" to US national security, alleging that "The regime aligns itself with and provides support for numerous hostile countries, transnational terrorist groups,...