Following a meeting on the sidelines of the summit in Osaka between Trump and Russian President Vladimir Putin, reporters asked the U.S. president if he would issue the Russian leader a warning against meddling in U.S. elections.
"Yes, of course, I will," he said before turning to Putin. "Don't meddle in the election."
The comment, seemingly made in jest, came after the two held a bilateral meeting, during which they discussed Iran, Syria, Venezuela and Ukraine while agreeing to improve relations as it was in "each countries' mutual interest and the interest of the world," according to the White House.
"We have a very good relationship and we look forward to spending some very good time together," Trump said. "A lot of very positive things are going to come out of the relationship."
This was the first meeting between the pair since former special counsel Robert Mueller released a report that said Russia meddled in the 2016 presidential election.
Trump has repeatedly denied the findings, calling the 22-month investigation the report was based on a "witch hunt."
Putin pointed out following their meeting that they had not seen one another since their first summit in Helsinki, Finland, last July when Trump said Putin denied the election meddling allegations.
Their time together in Osaka would be a "great opportunity to follow up on that," he said.
"The president urged Merkel to join the U.S. in keeping Iran under maximum global pressure," the White House said on Twitter.
Relations have been strained between the two countries since Trump took office as he has raised the issue with Germany falling short of its NATO defense spending goals as well as other issues.
During the meeting Friday, however, he joked with Merkle about the second televised Democratic debate, saying "I look forward to spending time with you, rather than watching."
He told reporters following the meeting that Merkle is "a fantastic person, a fantastic woman and I'm glad to have her as a friend."
He also held a bilateral meeting with Japanese Prime Minister Shinzo Abe, before which Abe said sustainable growth of the world's economy wouldn't be possible "without the cooperation of the U.S. and Japan."
Trump said it was a "great honor to be your first guest" and joked that he had just left Japan and now he's back.
"I know we're going to have a successful day," Trump said. "We're going to be talking about many things, and we're going to also be talking about a lot of trade."
He then thanked Japan for "sending" its car companies to the United States.
"The car companies have been terrific," he said. "They're coming in and they're building magnificent plants. We haven't had that, and we very much appreciate it."
He also said they will be discussing trade and military.
"And we'll be discussing the purchase of a lot of military equipment by Japan, and we appreciate that," Trump said.
The meeting came amid rising tensions between the two countries after Trump criticized Japan before the trip for the unequal military balance it shares, saying the United States would defend its Asian partner but if the United States was attacked, Japan would "watch [the war] on the Sony television."
The two also held a trilateral meeting with Indian Prime Minister Narendra Modi where they renewed their commitment to global security and infrastructure development, the White House said.
Trump also held a one-on-one meeting with Modi where they discussed 5G technology with the focus on security, Iran and trade, said advisor to the president and Trump's daughter Ivanka Trump in a video posted on Twitter by the White House.
"We've become great friends and our countries have never been closer," Trump said. "I can say that with a surety and we will work together in many ways, including military but we certainly will work together on trade and we will be discussing trade today."