Brent fell toward US$64 a barrel, while West Texas Intermediate was near US$60.
The leaders of the two largest economies are expected to finalise a trade deal at the meeting in South Korea, which began this morning.
Trump may also use the exchange to lean on Beijing to curb the buying of Moscow’s oil after his administration imposed sanctions on two Russian producers.
“The possibility of some deal is likely,” said Mukesh Sahdev, founder and chief executive officer of Xanalysts Pty.
“Still, the topic of oil and China’s Russian buying may be further down their priority list,” he said.
Crude remains on track for a third monthly decline, the longest losing run since the third quarter (Q3) of last year.
Prices have been hurt by expectations that supply hikes from Opec+ as well as rival drillers will drive production above demand.
The International Energy Agency has warned that the surplus in 2026 will be a record, although Saudi Aramco has struck a more positive tone.
In South Korea, the two leaders shook hands at the start their first in-person discussions since Trump returned to office in January, with the US president saying that “we’re going to have a very successful meeting.”
Initial signals indicated they are set to agree on a pact that could see a rollback of some tariffs, fees and curbs threatened or implemented in recent months.
Opec+, meanwhile, has a meeting on supply on Nov 2.
The alliance is expected to focus on reviving another sliver of production in December in a move that may amplify traders’ concerns about a global glut.
“The group is likely to boost output quotas by a modest 137,000 barrels a day for December despite the US sanctions on Russia’s Rosneft PJSC and Lukoil PJSC threatening to squeeze global supply,” RBC Capital Markets LLC said in a note.
“Brent is set for more choppy trade,” said Robert Rennie, head of commodity and carbon research at Westpac Banking Corp, citing factors including the sanctions on Russian oil producers.
“We stick to the view that we are now back in a US$60-to-US$65 trading range, with an eventual break below US$60,” Rennie said.