ROME >> After a six-week diplomatic spat that involved a scuttled nuclear-powered submarine deal and a recalled ambassador, President Joe Biden began a one-on-one effort to mend fences with President Emmanuel Macron of France by saying the U.S.’ handling of the matter had been “clumsy.”

“What we did was clumsy,” Biden told reporters, sitting beside Macron just before they began a private meeting. “It was not done with a lot of grace.”

He added, “I had been under the impression long before that France had been informed.”

France had an agreement to build conventionally powered submarines for Australia’s navy, but last month the United States and Britain announced their own deal with Australia for nuclear-powered subs instead. Australia called off the deal with France, whose officials had not been told that a pact with the Americans and British was in the works, infuriating Macron and others in his government.

Washington’s European allies were already irritated by the handling of the withdrawal from Afghanistan, which they said Biden ordered without consulting them. The treatment of the French submarine deal, they said, was further evidence of American dismissiveness.

Since that agreement was sabotaged, the two countries have worked hard to overcome the dispute, and the Biden administration has sent officials to Paris, including Secretary of State Antony Blinken, to try to smooth things over. Unsatisfied with the niceties, France has demanded “concrete” results.

“Now what’s important is to be sure that such a situation will not be possible for our future,” Macron said in his own remarks to reporters. “This is an extremely important clarification.”

Some of those results the French have demanded may be forthcoming but were not announced when the two spoke to reporters before a lengthier diplomatic meeting.

American and French officials said the United States was prepared to bolster France’s counterterrorism efforts in Africa, including possibly sending additional reconnaissance planes and drones to the $110 million airfield that the United States has built in the desert scrub near Agadez, Niger.

The Biden administration will also try to address one of Macron’s priorities by giving a guarded backing to a European military force that is separate from NATO, the officials said.

It would also be viewed in Paris as a sign of American respect after the perceived insult of the secretly negotiated Australian submarine deal.

Officials said they hoped the U.S.’ moves would put to rest the fight between the United States and France.

“The United States is still our major ally,” said Gen. Thierry Burkhard, the French military’s chief of staff. “But what we need is a very clear sign that trust can still be there.”

With his domestic agenda in limbo and tensions with China and Russia smoldering, Biden kicked off a whirlwind international tour today in Rome, where he also met with Pope Francis to discuss global challenges like the pandemic and climate change.

The meeting — the president’s first with Francis since his inauguration — had deep emotional resonance for Biden, a Roman Catholic. The president and the pope share common ground on many issues, and Biden seemed visibly excited as he headed into a private meeting, which lasted 90 minutes.

During their meeting, Biden thanked Francis for his advocacy for the world’s poor and people suffering from hunger, conflict and persecution, the White House said, adding that he had also lauded the pope’s leadership in the climate crisis and his advocacy on coronavirus vaccines.

Francis has repeatedly called on pharmaceutical companies to waive intellectual property protections for their coronavirus vaccines on the grounds that doing so would be a “gesture of humanity.” In May, Biden said he supported the suspension of some of those protections, but large manufacturers have argued that increasing production is a more effective way to help end the pandemic.

After the Vatican visit, Biden is set to attend the Group of 20 summit, and then, he and many of the same leaders will travel to Scotland for COP26, a worldwide summit on climate change that is billed by many as a make-or-break moment to save a warming planet from disaster.

For Biden, the international events come against the backdrop of high-stakes negotiations over his domestic agenda. But participants in the summits from across the globe are all facing enormous challenges, many linked to the pandemic and the health and economic devastation it has wrought.

The agenda would be daunting even in normal times, but this is the first G-20 meeting in person since the virus emerged. Many of those who are coming hope to deliver concrete changes on issues like international tax shelters and getting coronavirus vaccines to the developing world, even as they struggle to make progress on existential issues like lowering carbon emissions and addressing energy shortages.

Between the meetings with Francis and Macron, Biden headed to the Chigi Palace, the home of Italy’s prime minister, Mario Draghi. It was not just a polite drop-by. With Chancellor Angela Merkel of Germany leaving the scene and Macron politically embattled, Draghi has emerged as a leader of Europe and a potentially key interlocutor for a U.S. president looking to keep alliances strong on the Continent.