Joe Biden is visiting Uvalde in Texas to comfort grieving families following a mass school shooting which left 21 people dead.
Outside Robb Elementary School, Mr Biden stopped at a memorial of 21 white crosses - one for each of those killed - and the first lady added a bouquet of white flowers to a pile in front of the school sign.
They viewed individual altars erected in memory of each student, and the first lady touched the children’s photos as the couple moved along the row.
Later, the president planned to meet privately with family members at a community centre and then with first responders at the airport before returning to Washington, the White House said.
Last Tuesday, a teenage gunman stormed Robb Elementary School in Uvalde killing 19 children and two teachers in the shooting.
Mr Biden’s visit comes amid mounting criticism over the police response to the shooting, the worst in the US in a decade.
“He has to stay focused on the pain and grief of the families and the community and understand that all of this has been compounded by the fact that we still don’t know exactly what happened.
“The more we learn, the more it seems the children were poorly served,” said Karen Finney, a Democratic strategist.
Anger has been building in the city of Uvalde since Tuesday and questions remain over why local police waited at least an hour to storm the classroom with the attacker inside.
It has emerged desperate parents begged with police to go in sooner before federal agents arrived and shot 18-year-old Salvador Ramos dead.
During a news conference, Texas Department of Public Safety director Steven McCraw said that it was “the wrong decision” not to storm the classroom earlier.
The visit to Texas is Mr Biden’s third presidential trip to a mass shooting site.
The Uvalde mass school shooting has once again put gun control at the top of the nation’s agenda, months ahead of the November midterm elections.
Supporters of stronger gun laws argue the latest bloodshed represents a tipping point.
“The president has a real opportunity. The country is desperately asking for a leader to stop the slaughter from gun violence,” said Igor Volsky, executive director of Guns Down America.
Vice President Kamala Harris called for a ban on assault-style weapons during a trip to Buffalo on Saturday, saying that in the wake of the two back-to-back mass shootings such arms are “a weapon of war” with “no place in a civil society.”
Meanwhile, the National Rifle Association has been holding its annual convention in Houston.
On Friday, former US President Donald Trump told the convention that the US should prioritise funding for school security over sending money to Ukraine.
He told the pro-gun meeting that the country “should be building safe schools” before sending military aid sent to Ukraine.
“Before we nation-build the rest of the world, we should be building safe schools for our own children in our own nation,” he said.
