Slovyansk, Ukraine (CNN) -- Ten Russian soldiers were detained in the Donetsk region of eastern Ukraine, that country's Security Service said Tuesday, as tensions simmered over the conflict between Ukrainian forces and pro-Russian rebels. The Russian soldiers were captured with documents and weapons on them, the Security Service said. Moscow has repeatedly denied claims by Kiev that it has sent troops and weapons over the border into Ukraine, where the Ukrainian military is fighting pro-Russian rebels. Russia's state-run RIA Novosti news agency cited a source in the Russian Defense Ministry as saying the soldiers had been patrolling the border and "most likely crossed by accident" at an unmarked point.
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NEW: Russia's Putin says talks with Ukrainian President Poroshenko were positive
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Poroshenko had said earlier that talks could decide future peace of Europe
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Ukraine's Security Service says 10 Russian soldiers were detained in the Donetsk region
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Russian state media cites a source saying the soldiers crossed the border accidentally
Putin told reporters that @placeholder couldn't be involved in ceasefire talks because those discussions should be between Kiev and separatists in eastern Ukraine.
The move "is in no way aimed against anyone," @placeholder said, according to a statement from his office.
Russia denies direct or indirect involvement in the fighting and says @placeholder's assault against the rebels is precipitating a humanitarian crisis.