Kiev , Ukraine ( CNN ) At least seven civilians died after shells slammed into a transit stop Thursday in the volatile eastern Ukrainian city of Donetsk , the latest notable attack in a months-long conflict that has seen plenty of bloodshed , blame-sharing and intermittent negotiations but few signs of easing . The fatalities are among at least 10 civilians killed total , in addition to 20 injured , in the shelling of four city districts in the past 24 hours , the Donetsk City Council said on its website . Ukraine 's state-run Ukrinform news , citing the Donetsk government , reported eight dead and seven hospitalized in the bus stop attack alone . Donetsk has been a stronghold for separatists , who have been battling government forces for control of the Donetsk and Luhansk regions since the spring . `` As of now , the situation remains difficult , '' the city council said . And as has been the case with many incidents in the conflict , there was no universally accepted explanation of what happened or who was responsible . Russia 's Foreign Ministry demanded an investigation and criticized Ukraine for its shelling of Ukrainian cities like Donetsk , which are controlled or at least full of pro-Russian separatists . Yet Ukraine 's Defense Ministry blamed the rebels for the attack , saying it was launched from areas they control . The Organization for Security and Cooperation in Europe , which has a monitoring mission in Ukraine , is among those trying to get to the bottom of it all . Its deputy chief monitor , Alexander Hug , told reporters that an OCSE patrol saw seven bodies near a vehicle that had been hit . And it 's not the only instance of violence in the area . `` Terrorists using multiple launch missile systems precisely destroy ( ed ) houses '' in the Donetsk region cities of Debaltseve and Avdiyivka , Ukrinform reported , citing Donetsk regional police Chief Vyacheslav Abroskin . Rebels captured 16 wounded Ukrainian soldiers after fighting at Donetsk 's airport , Kiev 's military said , according to Ukrinform . Negotiations are underway to secure their release . And the OSCE , in an update posted Wednesday , cited numerous instances of shelling in recent days , with two hospitals in separatist-held territory among the buildings affected . As U.S. Gen. Philip Breedlove , NATO 's Supreme Allied Commander Europe , pointed out Thursday : `` Violence has intensified and changed character in Ukraine . '' As has been true so often in recent months , the violence is happening around the same time as negotiations aimed at stopping it . The latest talks happened Wednesday in Berlin and included the foreign ministers of Ukraine and Russia , as well as Germany and France . Their official aim was to resolve the crisis by hammering out how to implement a peace deal that was agreed upon last year . After Wednesday 's talks , the four foreign ministers condemned the continuing violence and called for the peace deal that was reached in Minsk , Belarus , last September to be respected . Fighting in the Donetsk and Luhansk regions `` has severely escalated causing the loss of many human lives including civilians . This must stop immediately and the regime of quiet must be restored , '' the ministers said . They said `` tangible progress '' must be made on full implementation of the Minsk pact ahead of a planned peace summit . The attack on the Donetsk trolley bus station obviously does n't help the situation . Russia 's foreign ministry called it a `` a crime against humanity ( and ) a great provocation aimed to undermine the efforts for the peaceful settlement of the crisis . '' The unrest began in late 2013 , leading up to Parliament 's ouster last February of pro-Moscow President Viktor Yanukovych . Russia annexed the Crimean Peninsula a few weeks later , with fighting breaking out in April in two Ukrainian regions bordering Russia -- Donetsk and Luhansk . Separatist leaders there declared independence from Ukraine and sided with Russia . But how much was , and is , Moscow involved in their campaign ? Ukraine 's divide : Two sides of a river . It depends who you ask . Officials in Moscow have expressed sympathy for the separatists , but denied any outright military support . However , Ukraine and its allies have accused Russia of fomenting the rebellion by actively backing it . `` It is clear that Russia has to stop supporting the separatists and respect international law , '' said Danish Gen. Knud Bartels -- chairman of the military committee for NATO , which does n't include Ukraine but is working to further its `` military-to-military cooperation '' with Kiev . On Wednesday , Ukrainian President Petro Poroshenko reasserted a claim that Russia sent troops across the border to support the rebels . `` We have more than 9,000 Russian troops who -- so-called -- lost the way , crossing our Russian-Ukrainian border , bring with them hundreds and hundreds of tanks , armed personnel carriers , and killing Ukrainian civilians and attacking Ukrainian troops , '' Poroshenko told CNN . Russian Foreign Minister Sergey Lavrov , speaking in Moscow before the Berlin talks , responded to Ukraine 's assertion with a firm denial -- much like other denials made by Russian officials in recent months over similar allegations of armed intervention . `` As to the flow of troops and armaments , this is not the first time we hear something like that , '' he said . `` And each time I hear that I say , if you 're so confident about that , please present us with facts , but no one has been able to provide us with these facts . '' Journalist Victoria Butenko reported from Kiev . CNN 's Alla Eschenko , Christine Theodorou , Khushbu Shah and Stefan Simons contributed to this report .
State news : Rebels capture 16 wounded Ukrainian soldiers at Donetsk 's airport . 16 civilians reported killed in shelling in Ukraine city , seven of them at a bus stop . Donetsk 's Defense Ministry blames Ukrainian rebels ; Ukraine demands an investigation .