For the first time as commander in chief, Trump laid a wreath at the Tomb of the Unknown in Arlington, Va., on Monday
"Thank you for joining us as we honor the brave warriors who gave their lives for ours -- spending their last moments on this earth in defense of this great country and its people," Trump said. "We only hope that every day we can prove worthy, not only of their sacrifice and service, but of the sacrifice made by their families and loved ones they left behind -- special, special people."
"I especially want to extend our gratitude to Gen. Kelly for joining us today -- an incredible man -- I always call him general," Trump said. "He understands more than most ever could, or ever will, the wounds and burdens of war."
Trump added: "To the entire Kelly family, today, 300 million American hearts are joined together with you. We grieve with you. We honor you and we pledge to you that we will always remember Robert and what he did for us."
Trump spoke for the first time since returning to the United States on Saturday from his nine-day trip abroad.
Trump also posted comments about Memorial Day on Twitter, including: "Honoring the men and women who made the ultimate sacrifice in service to America. Home of the free, because of the brave. #MemorialDay."
Trump also laid a wreath at the tomb the day before he was inaugurated on Jan. 20.
Joining Trump was Vice President Mike Pence, who earlier played host at his residence to more than 200 motorcycle riders as part of Project Hero, an organization for veterans and first responders. The bikers rode from Washington, D.C., to Virginia Beach.
He posted on Twitter: "Thank you, Project Hero, for the new biking jerseys for Karen and me. May you all have a safe ride to Virginia Beach!"