The United States and Western allies pressured Russia at G20 talks in Indonesia Friday over its "unprovoked and unjustifiable war of choice" in Ukraine, but Moscow's envoy remained defiant.

US Secretary of State Antony Blinken and Russian counterpart Sergei Lavrov joined colleagues for day-long talks in their first meeting since the outbreak of war, with the host immediately telling them the conflict must end through negotiations.

Before the meeting on the resort island of Bali, Blinken met his French and German counterparts and a senior British official to discuss "Russia's unprovoked and unjustifiable war of choice" in Ukraine, the State Department said in a statement.

They "reviewed ways to address the global food security concerns that have resulted from Russia's deliberate targeting of Ukrainian agriculture", it said.

Blinken will shun a direct meeting with Lavrov, US officials said, instead accusing Moscow of triggering global food and energy crises.

In response, Lavrov told reporters he would not "go running" after the United States for talks.

"It was not us who abandoned contact, it was the United States," he said, adding that no ministers walked out of the talks.

"Our Western partners are trying to avoid talking about global economic issues," he added. "From the moment they speak, they launch into fevered criticism of Russia."

The gathering was overshadowed by the shooting of former Japanese Prime Minister Shinzo Abe at a campaign event on Friday, with Japanese premier Fumio Kishida saying he is in a "very grave condition".

Blinken voiced alarm and called it a "very sad moment" after the attack on a longtime ally of Washington and Japan's longest-serving premier.

Indonesian Foreign Minister Retno Marsudi, chair of the meeting, said Jakarta conveyed its "deepest sympathies" to Japan.

Before the news emerged, she addressed the war in a speech to the ministers including Lavrov.

"It is our responsibility to end the war sooner than later and settle our differences at the negotiating table, not the battlefield," Marsudi said.

In the session that followed, there was strong and "nearly unanimous" condemnation of Russia, a source in the meeting told AFP.

- No family photo -
A US official indicated Washington did not want to embarrass Indonesia at the meeting by walking out on Lavrov.

The hosts have addressed US concerns about Lavrov attending in part by inviting Ukrainian President Volodymyr Zelensky to the G20 summit later this year and Foreign Minister Dmytro Kuleba to Friday's meet.

But there will be no family photo of the G20 ministers as is customary, an Indonesian government official told AFP.

Blinken arrived at the Mulia hotel on Friday where he could be seen talking with South Africa's foreign minister before entering the same room as Lavrov, who he last met in January.

Russia's top diplomat was seated between the Saudi Arabian and Mexican foreign ministers as the meeting began.

He was later seen strolling and chatting to Indian Foreign Minister Subrahmanyam Jaishankar before he met with Blinken.

In his meeting with Delhi's envoy, Blinken said many of the G20 member countries had criticised Moscow over its campaign in Ukraine.

"What we've heard today already, is a strong chorus from around the world... about the need for the aggression to end," he said.

- British FM leaves -
Friday's meeting is a prelude to the leaders' summit on Bali in November that was meant to focus on the global recovery from the Covid-19 pandemic.

Blinken's efforts to have a powerful Western stance against Russia at the meeting were diluted after British Foreign Minister Liz Truss pulled out following Prime Minister Boris Johnson's resignation as leader of his party on Thursday.

She flew out of Bali on Friday morning and was replaced by former British ambassador to the European Union Sir Tim Barrow, a British official told AFP.

While in Bali, Blinken will also seek to reopen dialogue with Beijing in talks on Saturday with his Chinese counterpart Wang Yi, the first in months after tensions became strained over issues including Taiwan.

The meeting comes as US President Joe Biden voices hope for a conversation in the coming weeks with Chinese President Xi Jinping, with whom he last spoke in March.

Lavrov met Wang on Thursday to discuss Russia's invasion, which Moscow says it launched to stop Ukraine from joining the NATO military alliance.

The United States has condemned Beijing's support for Russia, and Blinken is expected to reiterate those warnings in talks with Wang.

Australian Foreign Minister Penny Wong will herself meet Wang on the sidelines of the meeting on Friday to press China to end trade "blockages", she said.