BIARRITZ, FRANCE (AP) - Injecting fresh uncertainty at a time of global economic jitters, US President Donald Trump sent mixed messages on Sunday (Aug 25) on the United States-China trade war as leaders at a global summit pushed the unpredictable American president to ease frictions over tariffs and cooperate on other geopolitical challenges.

Mr Trump's head-snapping comments at the Group of Seven summit about his escalating trade fight with China - first expressing regret, then amping up tariff threats - represented just the latest manifestation of the hazards of the president's go-it-alone mantra. Allies fault his turbulent trade agenda for contributing to a global economic slowdown.

Despite Mr Trump's insistence that reports of US tensions with allies are overblown, fissures between the US and six of the world's other advanced economies were apparent on trade policy, Russia and Iran as the leaders gathered at a picturesque French beach resort.

Two days after the US and China traded a fresh round of retaliatory tariffs and Mr Trump threatened to force US businesses to cut ties with China, the president appeared to harbour qualms about the trade war, which has sent financial markets tumbling.

Asked during a meeting with British Prime Minister Boris Johnson if he had any second thoughts about escalating the trade conflict, Mr Trump told reporters, "Yeah. For sure." He added: "I have second thoughts about everything."

Hours later, the White House backpedalled. Press secretary Stephanie Grisham issued a statement saying the press had "greatly misinterpreted" Mr Trump's comments. She said the president only responded "in the affirmative - because he regrets not raising the tariffs higher".

White House economic adviser Larry Kudlow, who was in the room when Mr Trump spoke and was later interviewed by CBS' Face The Nation, offered his own explanation.

He claimed Mr Trump "didn't quite hear the question" although reporters asked the president three times whether he had any second thoughts about ramping up the trade war and he responded three times.

At first, Mr Trump's admission appeared to mark a rare moment of self-reflection by the famously hard-nosed leader. The subsequent explanation fits a pattern of Mr Trump recoiling from statements he believes suggest weakness.

Earlier this month, Mr Trump backed off on a threat to place even tougher tariffs on Chinese imports as aides fretted about their impact on the holiday shopping season and growing fears of a recession in the US.

Mr Trump had hoped to use the summit to rally other leaders to do more to stimulate their economies, as fears rise of a potential slowdown in the US before he stands for re-election in November 2020.

Mr Johnson, for his part, praised Trump for America's economic performance - but chided the US leader for his unbending China policy.

"Just to register a faint sheep-like note of our view on the trade war," he told Mr Trump, "we're in favour of trade peace."

Mr Trump said he had "no plans right now" to follow through on his threat of an emergency declaration, but he insisted he would be within his rights to use a 1977 law designed to target rogue regimes, terrorists and drug traffickers as the newest weapon in the clash between the world's two largest economies. "If I want, I could declare a national emergency," he said.

He cited China's theft of intellectual property and the large US trade deficit with China, saying "in many ways that's an emergency".

For all of that, Mr Trump disputed reports of friction with other G-7 leaders, saying he has been "treated beautifully" since he arrived.

The cracks started to emerge moments later after the French government said the leaders had agreed at a Saturday dinner that French President Emanuel Macron would deliver a message to Iran on behalf of the group.

Mr Trump denied he had signed off on any such message.

"No, I haven't discussed that," he told reporters during a meeting with Japanese Prime Minister Shinzo Abe.

Administration officials said Mr Trump was noncommittal when the leaders discussed the subject of a message to Iran during a conversation about Iran's nuclear programme.

For several months, Mr Macron has assumed a lead role in trying to save the 2015 nuclear accord, which has been unravelling since Mr Trump pulled the US out of the agreement. The French went even further on Sunday, inviting Iranian Foreign Minister Jawad Zarif to Biarritz in a bid to open talks meant on lowering tensions.

Mr Trump curtly told reporters he had "no comment" on Mr Zarif's presence. Officials said the White House was not aware in advance of the invitation to Mr Zarif - a further indication of Mr Trump's diminished role.

Mr Trump also faced opposition from European leaders over his stated desire to find a way to re-admit Russia to the G-7 before next year's meeting of the world leaders, which will be held in the US. Russian President Vladimir Putin was expelled from the former G-7 in 2015, following Moscow's invasion of Ukraine.

And, sitting feet away from Mr Abe, Mr Trump declined to forcefully condemn North Korea's flouting of international sanctions with a recent burst of short-range ballistic missile tests, calling them "much more standard" missiles. Mr Abe views them as a critical security threat.

Mr Trump told reporters: "We're in the world of missiles, folks, whether you like it or not."