By Andrew Cawthorne and Eyanir Chinea CARACAS (Reuters) – The United States on Tuesday ordered three Venezuelan diplomats to leave in reprisal for President Nicolas Maduro’s expulsion of three American embassy staff accused of fomenting unrest that has killed at least 13 people. Disputes between the ideologically opposed governments in Washington and Caracas were common during the 1999-2013 rule of late socialist leader Hugo Chavez and have continued under his successor Maduro. When it comes to oil, though, pragmatism trumps politics and the United States remains the OPEC member’s main export market. The U.S. State Department said in a statement that two first secretaries and a second secretary at the Venezuelan embassy in Washington had been declared personae non gratae in response to Caracas’ February 17 move against the three Americans.