Early Friday morning saw heavy clashes in the pro-Russian rebel stronghold of Slovyansk, as Ukrainian troops hit multiple checkpoints around the city. They were met with heavy fighting from the rebels, who shot down two helicopters, killing two of the crew members. “Against Ukraine’s special forces, terrorists used heavy fire, including grenade launchers and anti-aircraft rocket launchers. It is the real battle with professional mercenaries,” said Interior Minister Arsen Avakov. Vladimir Putin said the Ukranian incursion destroyed the “last hope” for a previous diplomatic agreement to continue.