VATICAN CITY, Feb 1 - Pope Leo said on Sunday he was deeply concerned about rising tensions between the United States and Cuba, and he called for "sincere and effective dialogue" to prevent violence and further suffering for the Cuban people.

U.S. President Donald Trump said last week tariffs would be imposed on imports from countries that supply Cuba with oil, ratcheting up the pressure on Washington's long-time foe after ousting Venezuelan President Nicolas Maduro, a key Cuban ally, in early January.