WASHINGTON -- U.S. President Donald Trump arrived back in Washington after his nine-day trip to the Middle East and Europe, with media reports saying he is considering a major personnel shake-up at the White House.

His plane landed late on May 27 after a flight from Sicily, where he met with leaders of the Group of Seven (G-7) industrial powers to discuss trade, terrorism, and climate change.

Walking with first lady Melania, Trump waved to reporters as he went into the White House but made no comment.

The Washington Post, The New York Times, Reuters, and other media outlets reported that Trump is considering creating a so-called "war room" to deal with the growing number of questions about his presidential campaign and Russian meddling in the 2016 U.S. election.

Corey Lewandowski, who was fired as campaign manager nearly a year ago; David Bossie, who was deputy campaign manager; and chief strategist Stephen Bannon could lead the "war room,"” the reports said.

Other White House personnel changes are being considered as well, the reports said.

The potential moves come after media reports said the investigation into Russia's role in the election and influence afterward has moved to Trump's inner circle at the White House.

The Washington Post and The New York Times reported that Trump's son-in-law and top adviser, Jared Kushner, had sought a secret communications line with Moscow before Trump's January 20 inauguration.

In a press conference in Sicily on May 26, White House advisers H.R. McMaster and Gary Cohn declined to comment directly on the reports. "We're not going to comment on Jared. We're just not going to comment," Cohn said.

The White House chose to focus on the president's first foreign trip and what Trump called a "truly historic week."

G7 leaders announced that they had come to an agreement on establishing further steps to fight terrorism.

The leaders also said they had narrowed their differences on trade, with Trump tweeting that the G7 countries were looking to end “all trade-distorting practices."

"Just left the #G7Summit. Had great meetings on everything, especially on trade where... we push for the removal of all trade-distorting practices....to foster a truly level playing field," he wrote.

However, the U.S. president refused to commit to whether the United States would remain a part of the 2015 Paris climate-change agreement on curbing greenhouse gas emissions.

A final communique issued on May 27 said Britain, Canada, France, Germany, Italy, and Japan reaffirmed their "strong commitment" to the implementation of the accord.

The United States "is in the process of reviewing its policies on climate change and on the Paris Agreement and, thus, is not in a position to join the consensus on these topics," it added.

Trump on May 27 said in a tweet he will make a final decision in the upcoming week.

Trump concluded his first trip abroad with an address to U.S. military personnel and families at the Sigonella Naval Air Station in Sicily.

In his speech, Trump said the trip had been "a home run." He later added that he'd had "a truly historic week."

Regarding the earlier NATO meeting in Brussels, he said that "money is actually starting to pour into NATO from countries that would not have been doing what they're doing now had I not been elected."

It is not clear what money Trump was referring to, but Germany has pledged to increase defense spending with the target of reaching 2 percent of GDP.

Trump also said the United States was "behind NATO all the way."

With reporting by AP, Reuters, and AFP