The Covid-19 pandemic is no justification for the non-implementation of the agreements reached at the Paris summit of the Normandy Four, German Foreign Minister Heiko Maas said.

"The coronavirus pandemic has not made the implementation in eastern Ukraine easier, but the pandemic should not be an excuse," Maas told journalists in Berlin following a videoconference with his French, Russian, and Ukrainian counterparts earlier on Thursday.

"Many of the Paris decisions have still not been implemented," he said.

"Together, we want to try and make sure they are," Maas said.

The four ministers have now agreed that the monitoring mission of the Organization for Security and Co-operation in Europe must continue working in the eastern parts of Ukraine, Maas said.

"It should be allowed to work uninhibited in the separatist region," he said. It is also necessary to establish a durable, verifiable ceasefire, and this too was discussed during the videoconference.

"We agreed that we want to realize the ceasefire," Maas said.

The ministers also discussed the need to set up new checkpoints on the dividing line, in addition to the current five, he said. "New crossings should be created there; there are too few of them, at the moment," Maas said.

Another topic discussed during the videoconference was prisoner exchange. There have been two since last December, which brought "much joy, but more exchanges are needed," he said.