United States president, Donald Trump visited his wife, Melania in hospital on Tuesday after the First Lady undergone a successful kidney surgery.

48-year-old Melania underwent an embolisation procedure to treat a benign kidney condition.

Trump spent about 90 minutes at the Walter Reed National Military Medical Centre, in Maryland before returning to the White House.

Also read: Melania Trump Undergoes Kidney Surgery

"Melania is doing really well. She's watching us right now," Trump said Tuesday as he spoke near the Capitol at an annual tribute to law enforcement officers killed in the line of duty.

"And I want to thank the incredible doctors," Trump added. "They did a fantastic job."

Trump tweeted Tuesday that his wife "will be leaving hospital in 2 or 3 days." Her spokeswoman had said in a statement Monday that the first lady was likely to remain hospitalized for "the duration of the week."

The White House said the procedure was "successful" but withheld details of the first lady's condition, citing her privacy.

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