Story highlights Trump finished up his nine-day trip in Italy

He spoke at US Naval Air Station Sigonella before leaving for Washington

Naval Air Station Sigonella, Italy (CNN) President Donald Trump couldn't return home from his first foreign trip without taking a quick victory lap.

But even as he touted the successes of his nine-day sweep through the Middle East and Europe before boarding Air Force One, Trump appeared eager to delay his return to Washington, where a storm of controversy awaits him.

"Maybe I'll stay down with you and celebrate together and just wave," Trump joked to the several hundred US service members and their families who crowded into an airplane hangar here to see him off.

Air Force One landed shortly after 9 p.m. ET Saturday at Joint Base Andrews outside Washington, and he and first lady Melania Trump left by helicopter for the White House.

Now that he's back in Washington, he will have to confront the latest developments in the federal investigation into members of his campaign's potential collusion with Russian officials during the 2016 election. Most notably, soon after Trump touched down in Sicily for the final leg of his trip, news surfaced that the FBI is now looking into the role his son-in-law and senior adviser Jared Kushner held during the campaign and transition, including his contacts with Russian officials.

Read More