Despite living in a tiny cellar in Donetsk for more than three months, Sergei is not complaining about the frequent shelling or lack of running water. Instead, he saves his fury for his own country -- Ukraine.

"It's the Ukrainian army that has done all this damage," the 56-year-old former miner rages, standing in front of the dusty mattress he sleeps on as his wife watches with pursed lips.

Five civilians, including two children, and three more Ukrainian soldiers have died in the latest fighting in Ukraine, officials said Saturday.

The civilian deaths came in Gorlivka, some 30 kilometers north of the rebel stronghold of Donetsk, late Friday, the local council in the rebel-held city said.

Secret "Russian subs" off Sweden, tit-for-tat sanctions, NATO fighters scrambling to intercept Russian warplanes: relations between the West and Moscow over Ukraine have sparked incidents reminiscent of the Cold War that terrified the world for decades.

Even Cold War doyen Mikhail Gorbachev used the highly symbolic 25th anniversary of the fall of the Berlin Wall to warn the world was "on the brink of a new Cold War", adding that "some are even saying that it has already begun".

President Vladimir Putin on Friday slammed G20 member countries for imposing sanctions on Russia, saying this violated the group's principles, but said he did not plan to raise the issue at the summit in Australia.

Putin told the TASS state news agency in an interview published Friday, ahead of this weekend's G20 summit in Brisbane, that sanctions against Russia violated the G20's principles and were "harmful".

Sweden said Friday it had evidence that a mini submarine entered its waters in October, in a Cold War-style incident that triggering a week-long hunt fuelled by heated speculation of a Russian incursion.

"The Swedish defence forces can confirm that a mini u-boat violated Swedish territory. This is a serious and unacceptable violation by a foreign power," the Supreme Commander of the Swedish Armed Forces Sverker Goeransson told reporters.

A five-year-old girl, a mine company worker and four government soldiers were killed Friday during fighting in war-torn east Ukraine, officials said.

The child died and her mother was seriously wounded when rebel mortar fire hit a village near the frontline northwest of the major rebel stronghold of Lugansk, a military spokesman in Kiev and local officials said.

Hungary's Prime Minister Viktor Orban on Friday dismissed corruption claims cited by Washington as the reason for U.S. entry bans on six senior Hungarian officials in October that have soured already frayed bilateral relations.

"This is just a scrap of paper," Orban on Friday morning in an interview with state radio, referring to a document published by the government on Thursday said to come from the U.S. embassy in Budapest.

Russia on Friday warned France of "serious" consequences unless Paris delivers by the end of this month a Mistral-class assault warship whose handover has been delayed by concerns over Moscow's role in the Ukraine crisis, a report said.

"We are preparing for different scenarios. We are waiting until the end of the month, then we will lodge serious claims," the state news agency RIA Novosti quoted an anonymous high-ranking Moscow source as saying.

Russia could face further sanctions if it does not commit to resolving the conflict in Ukraine, British Prime Minister David Cameron said Friday, as he called Moscow's actions "unacceptable".

Cameron, who was in Canberra to address Australia's parliament, said existing sanctions imposed by the West were having an impact on Russia's economy.

The United States on Thursday said Russia had boosted its military flights near U.S. shores and brusquely warned Moscow to abide by international law.

Washington's concerns came only days after a European think tank warned that since Russia annexed Ukraine's southern Crimea peninsula earlier this year, "the intensity and gravity of incidents involving Russian and Western militaries and security agencies has visibly increased."