WASHINGTON -- Melania Trump gave a splashy launch Monday to her public awareness campaign to help children, calling it "Be Best." In a rare twist on their White House roles, she commanded the Rose Garden lectern while President Donald Trump watched from the audience.

will focus on childhood well-being, social media use and opioid abuse.

"As a mother and as first lady, it concerns me that in today's fast-paced and ever-connected world, children can be less prepared to express or manage their emotions and oftentimes turn to forms of destructive or addictive behaviour such as bullying, drug addiction or even suicide," she said.

"I feel strongly that as adults, we can and should 'be best' at educating our children about the importance of a healthy and balanced life," she added.

Trump embraced his wife after she finished her speech and kissed her cheeks five times in a rare public display of affection. They held hands as they walked into the Oval Office after Trump signed a proclamation declaring Monday as "Be Best" day.

"America is truly blessed to have a first lady who is so devoted to our country and to our children," he said before signing the declaration.

The first lady kicked off the event as the White House pushed back against a published report that referenced rumours Mrs. Trump does not live with the president, with press secretary Sarah Huckabee Sanders denouncing it as "outrageous" and "ridiculous."

"The first lady lives here at the White House. We see her regularly," Sanders told reporters. "I think that's something that belongs in tabloid gossip, not on the front pages of The Washington Post. And I hope that they'll do better next time."

The first lady lived full-time in New York during the administration's opening months so the couple's son, Barron, now 12, would not have to change schools midyear. She and Barron moved into the White House last June and since then the first lady has gradually been raising her public profile.

Mrs. Trump joined her husband last month to host the prime minister of Japan for a two-day summit at the Trumps' Florida estate, and the Trumps hosted the president of France at the White House on a three-day state visit, including a lavish state dinner. Mrs. Trump also represented the administration at the April funeral of former first lady Barbara Bush.

Mrs. Trump's launch of her platform came as her husband faces questions over $130,000 in hush money paid by one of his attorneys to a porn actress who says she had sex with Trump in 2006. Trump has acknowledged reimbursing his lawyer for the payment to Stormy Daniels, but denies her allegations. Separately, a former Playboy model has revived her allegations of a 10-month affair with Trump in 2006. Trump also denies the allegations from Karen McDougal.

Such reports have kept the first lady's relationship with her husband under intense scrutiny, and Mrs. Trump has, at times, has been noticeably absent from her husband's side. But both made a point of displaying affection during the Rose Garden event.

A brief video that played before the first lady appeared recapped some of her public appearances with children. Several Cabinet members attended, including Treasury Secretary Steven Mnuchin and Transportation Secretary Elaine Chao, along with Vice-President Mike Pence and his wife, Karen. The first lady's mother, Amalija Knavs, was also in the audience.

During nearly 16 months as first lady, Mrs. Trump has demonstrated her interest in children. She visited young hospital patients in the U.S. and during overseas trips with the president, often reading to them and encouraging them to do their best.

Her interest in the opioid drug crisis has taken her to care centres and hospitals in West Virginia and Ohio to learn about the epidemic's effect on babies born to mothers addicted to the powerful painkillers. She convened a White House roundtable on the issue last fall.

The first lady invited representatives of major online and social media companies to the White House in March to discuss internet safety, a meeting that came more than a year after she promised to use her White House platform to discourage cyberbullying. Her choice was ridiculed almost immediately, given her husband's habit of name-calling on Twitter, but Mrs. Trump said at the meeting that she wouldn't be discouraged from doing what she thinks is right.

Sanders also pushed back Monday against the notion that the president has worsened online bullying.

"When it comes to kids, this is something that has been problematic, and something that we have seen over the last decade," Sanders said. "And the first lady sees it to be an important issue, and something that she wants to address."

Written material distributed in support of the initiative includes a booklet adults can use to talk to children about being online. It is similar to one the Federal Trade Commission released during the Obama administration. A spokeswoman for the first lady said the agency asked Mrs. Trump to include the booklet in her materials. The agency also wrote a blog post thanking the first lady for distributing it.

Modern first ladies typically highlight personal causes.

Nancy Reagan encouraged kids to "Just Say No" to drugs, while Barbara Bush and Laura Bush emphasized literacy and education. Michelle Obama launched her "Let's Move" campaign against childhood obesity about a year after moving to the White House.