The kidnappers said they will not release the students until they have achieved their separatist goals.
Ukraine's president has dismissed the move as coming straight from the Kremlin.
Fighting flares in Avdiivka as electricity and water links fail for its trapped residents.
Thai authorities step up security at landmarks and airports after reports of foiled plots.
The region has been a breakaway strip of land since 1990.
A Ukrainian national was arrested driving into rebel-held Horlivka with hidden cash.
Police said the suspect had separatist connections and was from a Muslim-majority province.
Investigative group Bellingcat report "thousands of Russian servicemen" active in eastern Ukraine.
Over 30 armored vehicles were recorded crossing what appears to be Luhansk city.
$3 billion is chump change for Putin, but payment could drive Ukraine into an acute currency crisis.
Ukraine's president will visit eastern regions on Wednesday but has not responded to the invite.
A vote on more autonomy for the eastern regions occupied by pro-Russian forces sparks violence.
Members of the battle-hardened Azov battalion are feeling sidelined.
Russian-backed artillery bombardment of Sartana, Ukraine, spurs the mayor to visit the library for inspiration.
'The notion that there is, or ever was, a cease-fire in eastern Ukraine is a farce.'
The pro-Russian separatists have access to a radioactive bunker. Kiev fears they plan to weaponize it.
Donetsk rebels have dismissed the president's proposal as "Kiev trickery."
Russia denies sending troops to help separatist fighters in east Ukraine and says Alexander Alexandrov went on his own.
Attack puts pressure on G7 leaders meeting this weekend to tighten the sanctions against Putin and his oligarchs.
Thousands have already died in the conflict, but Russia has denied involvement.
Mariupol is on the road to Crimea, but taking the city is far beyond the rebels' reach without Putin's troops.
Radical views and the use of symbols echoing Nazi emblems have caused alarm in the West and Russia.
The eight-day event opens tomorrow, with organisers saying the focus is on a positive outlook for the country.
For Ukrainian civilians, the first two months of 2015 have been especially deadly.