MARIUPOL, Ukraine (Reuters) - Scanning the sky for incoming artillery fire has become a force of habit for Ukrainian beetroot-seller Svetlana Kumurzhi, who dived under her wooden stall in government-held Mariupol when shells rained down a month ago.
While a fragile two-week-old ceasefire shows signs of holding, Kiev says pro-Russian separatists are using the truce to regroup their forces, especially around Mariupol, a strategically important port city in Ukraine's southeast.
