Surging casualties are threatening to undermine Ukraine’s campaign to regain ground from pro-Russian militants in its easternmost cities, where insurgents killed four government troops and downed a military helicopter. Four government servicemen died yesterday in fighting that may have killed about 30 rebels, acting Interior Minister Arsen Avakov said on his Facebook account. French President Francois Hollande said he warned Russian President Vladimir Putin that Europe would continue to pressure him to let Ukraine hold a May 25 presidential election and if it is thwarted, “chaos and a risk of war” would follow. “We must do everything to avoid civil war,” Hollande said on France ’s BFM TV-RMC radio today. “You know when it starts but never when it ends.” Efforts by the government in Kiev to expel insurgents from the easternmost regions are at risk of stalling less than three weeks before the ballot. German Chancellor Angela Merkel […]