European security watchdog OSCE has lost contact with one of its teams of election monitors near the eastern Ukrainian town Donetsk, where rebels are fighting with government forces.
The four-strong team were last heard from at around 6pm on Monday.
In a statement it said: "We are continuing with our efforts and utilising our contacts on the ground. The Ukrainian government as well as regional authorities have been informed."
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Leicester are Premier League champions after Tottenham conceded a two-goal lead in a bad-tempered 2-2 draw at Chelsea.
Football fans and players from all over the world savoured Leicester City Premier League triumph on Monday night.
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