(CNN) President Donald Trump broke his closely watched silence on Sen. John McCain, tweeting his "deepest sympathies and respect" to the family of the senator after his death was announced on Saturday night.

"My deepest sympathies and respect go out to the family of Senator John McCain. Our hearts and prayers are with you!" Trump tweeted.

My deepest sympathies and respect go out to the family of Senator John McCain. Our hearts and prayers are with you!

Prior to his tweet, Trump had not publicly acknowledged the rapidly declining health of McCain after his family announced Friday he would be discontinuing treatment for his brain cancer.

The President also posted the same message to his Instagram account. The accompanying photo , however, is not of McCain, but instead is of Trump.

In an email on Saturday evening, White House press secretary Sarah Sanders forwarded the President's tweet to reporters. First lady Melania Trump also tweeted, "Our thoughts, prayers and deepest sympathy to the McCain Family. Thank you Senator McCain for your service to the nation."

And Vice President Mike Pence also tweeted his condolences, writing that he and second lady Karen Pence "honor his lifetime of service to this nation in our military and in public life. His family and friends will be in our prayers. God bless John McCain."

Karen and I send our deepest condolences to Cindy and the entire McCain family on the passing of Senator John McCain. We honor his lifetime of service to this nation in our military and in public life. His family and friends will be in our prayers. God bless John McCain. — Vice President Mike Pence (@VP) August 26, 2018

Dan Scavino, Trump's longtime social media director said the flags at the White House have been lowered to half-staff in honor of the late senator.

This evening, the @WhiteHouse flag has been lowered to half-staff in honor of Senator John McCain... pic.twitter.com/tYdBNK9bA7 — Dan Scavino Jr. (@Scavino45) August 26, 2018

Trump's re-election campaign released a statement Saturday night, saying, "All of us at the Trump Campaign offer our sincere condolences to the family of Senator John McCain following his passing this evening. We encourage all Americans to take the opportunity to remember Senator McCain and his family in their prayers on this sad occasion."

McCain's death was duly noted by both Democrats and Republicans in Washington and elsewhere, as well as celebrities and world leaders, who released statements and tweets in support of the Arizona Republican.

In a statement following McCain's death, former President Barack Obama said, "Few of us have been tested the way John once was, or required to show the kind of courage that he did," and that he and Michelle "Send our most heartfelt condolences to Cindy and their family."

Senate Minority Leader Chuck Schumer, meanwhile, announced plans to introduce a resolution to rename the Senate's Russell office building after McCain -- a nod to the deep, bipartisan friendships McCain amassed throughout his career in the Senate.

But a mention of McCain's health was notably absent during a nearly hour-long speech by the President on Friday in Ohio.

Trump did, however, express support for the senator, a harsh critic of Trump, when his diagnosis was first announced last year.

"Senator John McCain has always been a fighter," the President said in a statement at the time. "Melania and I send our thoughts and prayers to Senator McCain, Cindy, and their entire family. Get well soon."

A White House official said Trump also called McCain following word of the senator's diagnosis.

In recent months, McCain continued to criticize the President in a series of tweets and statements that showed that while he was ailing he had lost none of his appetite for the political fight. The senator repeatedly made clear that he saw Trump and his America First ideology as a departure from the values and traditions of global leadership that he saw epitomized in the United States.

CNN reported in May that the McCains did not want Trump at his funeral. Former rivals and Presidents Barack Obama and George W. Bush had been asked to give eulogies, people close to both former presidents and a source close to the senator confirmed to CNN.

As a presidential candidate, Trump, who did not serve in the military himself, attacked McCain's record of service, saying the Vietnam veteran and former prisoner of war is "not a war hero" because he was captured. Trump later acknowledged that McCain was a hero, but refused to apologize in subsequent interviews.