LIMA (Reuters) – A three-day mourning period began in southern Peru on Tuesday after 17 more people were killed in the most violent day of protests since they began in December over the ousting of former President Pedro Castillo. The mourning period in the southeastern region of Puno came as Prime Minister Alberto Otarola was set to appear in the opposition-dominated Congress, seeking a vote of confidence in his cabinet – a constitutional requirement to lead a new government. Otarola regretted the deaths on Monday night and said the unrest was caused by organized attackers financed by “dark” m…