"Thank you to the Gold Star families that joined us in celebration & remembrance", Trump wrote in the tweet.
Mrs Trump made her global debut as first lady at last year's G7 summit in Italy, and went on to attend the G20 in Germany.
The White House confirmed that US sanctions will remain in place on North Korea unless the country agrees to abandon its nuclear program.
Two unnamed officials told CNN that Hagin did the same thing when Chinese President Xi Jinping was planning to visit Mar-a-Lago previous year.
However, Grisham confirmed to CNN that Melania would attend the reception for Gold Star families, honoring their family members who died in battle.
While Donald Trump was at Camp David with daughters Ivanka and Tiffany, son Donald Jr., and son-in-law Jared Kushner, Melania was notably absent.
The White House has declined to offer details about her health, aside to say that she was recovering.
Pochettino on Real Madrid: 'What will be, will be'
We will see each other soon, a hug'. "Hazard is a crowd-pleaser and definitely a big-name player that Madrid like to bring in". For many people, this will not make sense, but it does for me.
"She has had several meetings internally with staff and will continue to do so this week".
On Monday, during a meeting with the families of fallen soldiers, President Donald Trump quipped about speculation that the first lady had left him.
"Good to see her doing so well", said Ms Greene, whose father was killed in Iraq in 2004.
The first lady's attendance at such events is normal and several of Ms Trump's predecessors have hosted them. "I can't imagine a previous first lady disappearing for 24 days without some level of concern".
In April, she represented the Trumps at former first lady Barbara Bush's funeral, rolled out her "Be Best" awareness campaign to help children, and orchestrated an elaborate state dinner for the Macrons of France.
The President also talked about the strong economy during the event, the person inside the room said.