U.S. President Donald Trump said he and Russian President Vladimir Putin did not reach a deal to end Russia’s war in Ukraine after talks in Alaska on Friday, as the two leaders offered scant details on what was discussed but heaped praise on one another.

The US president said a peace agreement would be better than a "mere" ceasefire, hours after summit with Putin that produced little.

Russia says it invaded Ukraine to halt Kyiv's ambitions to join NATO, the U.S.-led defensive alliance, which it saw as a major security threat. It also accuses Kyiv of persecuting ethnic Russians and their culture in Ukraine.

The Ukrainian military said on Saturday that it had pushed Russian forces back by about 2 kilometres (1.2 miles) on part of the Sumy front in northern Ukraine. There was no immediate comment from Russia,