Update 7.20pm: President Donald Trump opened his first meeting with Russian president Vladimir Putin on Friday by raising US concerns about Moscow’s meddling in the 2016 presidential election, US secretary of state Rex Tillerson said.
He said Mr Putin denied being involved.
Mr Trump’s decision to confront Mr Putin directly over election interference fulfilled ardent demands by US politicians of both parties that the president not shy away from the issue in his highly anticipated meeting with Mr Putin.
Mr Trump has avoided stating unequivocally in the past that Russia interfered, even as investigations proceed into whether Mr Trump’s campaign colluded with Russians who sought to help him win.
Mr Putin’s denial of culpability notwithstanding, he and Mr Trump agreed that the issue has become a hindrance to better relations between the two powers, said Mr Tillerson, who attended the more-than-two-hour meeting along with Russia’s foreign minister.
Mr Tillerson said the discussion about the election meddling was "robust and lengthy".
Speaking to reporters after the meeting, Mr Tillerson said the two leaders had agreed to continue the discussion, with an eye toward securing a commitment that Russia will not interfere in US affairs in the future.
"I think the president is rightly focused on how do we move forward from something that may be an intractable disagreement at this point," Mr Tillerson said.
In their meeting, the two also discussed a ceasefire deal for southwestern Syria that was reached by Russia and the United States and first reported on Friday by The Associated Press.
Though the US and Russia have held conflicting views on Syria in the past, Mr Tillerson said Russia had an interest in seeing the Mideast nation become a stable place.
The heavily anticipated meeting has been closely scrutinised for signs of how friendly a rapport Mr Trump and Mr Putin will have.
Mr Trump’s predecessor, President Barack Obama, had strained ties to Mr Putin, and Mr Trump has expressed an interest in a better US-Russia relationship.
But deep scepticism about Russia in the US and ongoing investigations into whether Mr Trump’s campaign coordinated with Moscow during last year’s election have made a US-Russia detente politically risky for Trump.
The Putin meeting came midway through a hectic, four-day European visit for Mr Trump, who addressed thousands of Poles in an outdoor speech in Warsaw, Poland, on Thursday.
He met in Germany with Chancellor Angela Merkel, the summit host, and had dinner with two Asian allies, Japanese prime minister Shinzo Abe and South Korean President Moon Jae-in, to discuss North Korea’s aggression.
Update 5.11pm: The US and Russia have reached an agreement for a ceasefire in south-west Syria, according to officials.
The ceasefire is set to take effect at noon on Sunday.
Word of the ceasefire emerged as US President Donald Trump met Russian President Vladimir Putin at the G20 summit.
The deal marks a new level of involvement for the US in trying to resolve Syria’s civil war.
A separate deal to create "de-escalation zones" was brokered by Russia, Turkey and Iran, but not the US.
Follow-up talks this week in Kazakhstan to finalise a ceasefire in those zones failed to reach a deal.
The US and Russia have been backing opposing sides in Syria’s war.
Jordan and Israel also are part of the agreement, one official said.
The two US allies both share a border with the southern part of Syria and have been concerned about violence from the civil war spilling over the frontier.
Moscow has been supporting Syrian President Bashar Assad and Washington is backing rebels who have been fighting Assad. Both the US and Russia oppose the Islamic State group in Syria.
Previous ceasefires in Syria have collapsed or failed to reduce violence for long, and it is unclear whether this deal will be any better.
Earlier in the week, Syria’s military said it was halting combat operations in the south of Syria for four days, in advance of a new round of Russia-sponsored talks in Astana. That move covered the southern provinces of Daraa, Quneitra and Sweida.
Syria’s government briefly extended that unilateral ceasefire, which is now set to expire on Saturday - a day before the US-Russian deal would take effect.
The new agreement will be open-ended, one US official said, describing it as part of broader discussions with Russia on trying to lower violence in the war-ravaged country.
Officials said the US and Russia were still working out the details as Mr Trump and Mr Putin concluded their more than two-hour meeting on Friday.
The US has been wary of letting Iran gain influence in Syria - a concern shared by Israel and Jordan, neither of which wants Iranian-aligned troops massing near their territories.
A US-brokered deal could help the Trump administration retain more of a say over who fills the power vacuum left behind as Islamic State is routed from additional territory in Syria.
Though US and Russian officials had been discussing a potential deal for some time, it did not reach fruition until the run-up to Mr Trump’s meeting with Mr Putin on the sidelines of the G20 summit, officials said.
Earlier: Donald Trump has claimed there are "very positive things" in store for the US and Russia as he sat down with Vladimir Putin for a historic first meeting.
Seated next to the Russian president on the sidelines of the G20 summit in Germany, Mr Trump said it was "an honour" to be with Mr Putin.
As journalists were briefly allowed in to witness part of the meeting, the US president said that he and Mr Putin had already held "very, very good talks".
"We look forward to a lot of very positive things happening for Russia and the United States," Mr Trump said.
He offered no details about what issues he and the Russian leader had discussed, describing them only as "various things".
Mr Putin was similarly vague, telling reporters through a translator that they were discussing international problems and bilateral issues.
But he described the fact they were meeting as a positive sign in itself.
"Phone conversation is never enough," Mr Putin said, adding that he hoped the meeting would "yield positive results".
With secretary of state Rex Tillerson at his side, Mr Trump sat in front of an American flag with his hands clasped together.
Mr Putin, slightly hunched in his chair, rubbed his fingers together as he listened to Mr Trump address reporters. His foreign minister, Sergey Lavrov, sat nearby.
The highly anticipated meeting is the first between the pair, taking place under the shadow of US outrage about Russian election meddling and nagging questions about potential Trump campaign collusion.
The White House had said there was no set agenda for the session, although Mr Tillerson said the Syria war would be a key topic.