A tired Vladimir Putin has left Brisbane’s G20 praising the summit’s “constructive atmosphere” and saying the reported fallout between him and leaders of Western countries were exaggerated by the media.

Putin was the first world leader to leave Australia, his jet taking off shortly after 2pm local time.

The Russian president told reporters from his own country he was the first to go because he had to get back to Moscow to work, and he needed “four or five hours sleep”.

But Putin remained defiant over Russian interests in Ukraine, saying Kiev’s economic blockade of the separatist east was “a big mistake”, though “not fatal”.

“I don’t understand why Kiev authorities are cutting off those territories with their own hands. Well one can understand – to save money. But it’s not the time or the case to save money on,” he said.

Western leaders have queued up at G20 to condemn Russia’s actions in Ukraine, in particular supporting and arming separatist rebels, and for Russia’s perceived complicity in the downing of Malaysia Airlines flight MH17.

In his closing remarks, the Australian prime minister, Tony Abbott, told reporters he had had “a very candid and robust discussion” with Putin at Apec in Beijing, and that he suspected several leaders had had similar talks with the Russian leader at the G20.

“I have some differences with the Russian government, obviously,” Abbott said. “I don’t agree, in fact I utterly deplore, what’s happening in eastern Ukraine. I demand Russia fully cooperates with the criminal investigation into the downing of MH17.”

But Abbott said Putin was Australia’s invited guest for the G20 summit, and was treated as such.

“President Putin was a guest in our country, and I was a happy to treat him with respect and courtesy while he was here in Australia.”

The conflict in eastern Ukraine has killed more than 4000 people this year.

The UK prime minister, David Cameron, said he did not believe a new Cold War front was emerging, but that he was “robust” in his comments to the Russian leader, while the Canadian prime minister, Stephen Harper, said he told Putin bluntly to “get out of Ukraine”.

But Putin said there was a “good chance of resolution” of the Ukrainian conflict, and played down concerns military activity was escalating in the region.

He said discussion of Ukraine at the G20 was frank and informative.

“Some of our views do not coincide, but the discussions were complete, constructive and very helpful.”

In previous interviews, the Russian president has said he wants “normal relations with our partners, including the United States and Europe”, even as they threatened further sanctions.

Putin said his early departure from the Brisbane summit was unrelated to perceived tensions with other leaders.

He said he spoke personally to the Australian prime minister, Tony Abbott, and explained he had to undertake an 18-hour flight to get home before going back to work on Monday.

“We have to fly from here to Vladivostok nine hours, and then from Vladivostok to Moscow, another nine hours,” Putin told reporters.

“I came to Tony and told him about it, he understood this. There are no other considerations.”