KYIV/KRAMATORSK, Ukraine - Russian Foreign Minister Sergei Lavrov on Friday said attempts to isolate Moscow with sanctions was akin to a declaration of economic war by the West, dismissing what he said was "frenzied" criticism of the war in Ukraine.

Speaking at a G20 gathering in Indonesia, Lavrov said Russia would now turn to China and India and other nations outside the West. He scolded Russia's rivals for scuppering a chance to tackle global economic issues by focusing on Ukraine.

Russia's invasion its neighbour has triggered the most serious crisis in relations between Russia and Western nations since the 1962 Cuban Missile Crisis, when many people feared the world was on the brink of nuclear war.

Indonesia urged the G20 on Friday to help end the war, at a meeting that put foreign ministers from some of the staunchest critics of Russia's invasion in the same room as Moscow's top diplomat.

"Aggressors', 'invaders', 'occupiers' - we heard a lot of things today," Lavrov told reporters.

He said the West's discussion "strayed almost immediately, as soon as they took the floor, to the frenzied criticism of the Russian Federation in connection with the situation in Ukraine".

"During the discussion, Western partners avoided following the mandate of the G20, from dealing with issues of the world economy," Lavrov said.

Russia says its "special military operation" is intended to degrade the Ukrainian military and root out people it calls dangerous nationalists.

Ukraine and its Western backers say Russia is engaged in an imperial-style land grab. They say Russia has no justification for the war.

SNAKE ISLAND

Ukrainian President Volodymyr Zelenskiy said on Thursday the raising of the Ukrainian flag on Snake Island in the Black Sea was a sign his country would not be broken, as President Vladimir Putin warned Ukraine's allies that efforts to defeat him would bring tragedy to Ukraine.

In a hawkish speech to parliamentary leaders more than four months into the war, Putin said on Thursday that Russia had barely got started in Ukraine and the prospects for negotiation would grow dimmer the longer the conflict dragged on.

"We have heard many times that the West wants to fight us to the last Ukrainian. This is a tragedy for the Ukrainian people, but it seems that everything is heading towards this," he said.

Zelenskiy, in his nightly video message on Thursday, responded with defiance, saying that the two-month operation to retake Snake Island was a warning to all Russian forces.

"Let every Russian captain, aboard a ship or a plane, see the Ukrainian flag on Snake Island and let him know that our country will not be broken," he said.

Snake Island, a speck south of the port of Odesa, has become a symbol of Ukrainian determination.

In February, when ordered to surrender, the small Ukrainian garrison on the island swore at their Russian attackers and were hit by an air strike.

Russia abandoned the island at the end of June in what it said was a gesture of goodwill - a victory for Ukraine that Kyiv hoped could loosen Moscow's blockade of Ukrainian ports.

On Thursday Ukraine's raised its blue-and-yellow flag on the island. In response, Moscow stuck the island with war planes and destroyed part of the Ukrainian detachment there, it said.

The biggest conflict in Europe since World War Two has killed thousands, displaced millions and flattened Ukrainian cities. Kyiv and the West accuse Russian forces of war crimes, but Moscow says it does not target civilians.

Kyiv lost one of its main international supporters after British Prime Minister Boris Johnson said on Thursday he would step down. Moscow did not conceal its delight at the political demise of a leader whom it has long criticised for arming Kyiv.

Johnson's resignation comes at a time of domestic turmoil in some other European countries that support Kyiv and doubts about their staying power for what has become a protracted conflict.

PAUSE BEFORE FRESH FIGHTING

After failing to quickly take the capital Kyiv, Russia is now engaged in a war of attrition in Ukraine's eastern, industrial heartland of the Donbas, made up of the regions of Luhansk and Donetsk.

On Sunday, Moscow declared it had "liberated" the Luhansk region and now plans to capture parts of neighbouring Donetsk it does not control.

Russia is likely concentrating equipment on front line in the direction of Siversk, about 8 km (4.9 miles) west of the current Russian front line, Britain's defence ministry said on Friday.

Russian forces are likely pausing to replenish before undertaking new offensive operations in Donetsk, the Ministry of Defence said in a Twitter update.

The ministry said that Russia's immediate tactical objective might be Siversk, as its forces attempt to advance towards the Sloviansk-Kramatorsk urban area.

Serhiy Gaidai, governor of Luhansk, said Russian forces were indiscriminately shelling villages, towns and cities.

"They hit houses, every building that seems to them a possible fortification. To move forward, do not count personal losses and do not feel sorry for the inhabitants of the area," he said.

"The situation is similar in the settlements of the Donetsk region, which are located near the border with the Luhansk region."

Vadym Lyakh, the mayor of Sloviansk in the Donetsk region, said a woman was killed overnight when Russian shelling hit a residential building.

Reuters could not independently verify the battlefield accounts.

(Reporting by Reuters bureaux; Writing by Michael Perry; Editing by Robert Birsel and Frank Jack Daniel)