EU leaders unleashed a fourth round of hard-hitting sanctions on Russia and promised more military aid to Ukraine on Friday, the final day of an informal summit in Versailles near Paris. “We are committed to supporting Ukraine,” European Council President Charles Michel said after the summit, adding that a second tranche of €500 million ($550 million) in military aid would be disbursed. The European Union’s decision follows an historic agreement two weeks ago to finance the purchase and delivery of weapons and equipment to a non-EU country. The first defence contribution to Ukraine consisted o…