A prominent rebel leader in eastern Ukraine has been killed in an explosion in his office, his associates said on Wednesday. The rebels' Donetsk News Agency said Mikhail Tolstykh, better known under his nom de guerre Givi, died early Wednesday morning in what it described as a terrorist attack. The agency said 35-year old Tolstykh was killed by a rocket fired from a portable launcher into his office. Russian state television showed pictures of firefighters putting out flames in the building where Toltsykh's headquarters is believed to be. The footage from the scene showed several rooms in the building gutted...