US President Barack Obama is to lead the nation in honouring victims of the Dallas shooting.
He will visit the Texas city less than a week after five of its police officers were shot dead by an army veteran-turned-sniper during a brazen act of violence that Mr Obama denounced as a "vicious, calculated and despicable attack on law enforcement" by a "demented" individual.
Just a few weeks ago, he spent hours in Orlando, Florida, consoling the loved ones of 49 people who were killed in a shooting rampage at a gay nightclub.
In what has become a difficult but regular duty of his presidency, Mr Obama was preparing to address an interfaith memorial service in Dallas for the officers.
They were killed last Thursday while standing guard as hundreds of people peacefully protested over the police killings of black men in Louisiana and Minnesota earlier in the week.
The attack ended with the gunman, Micah Johnson, 25, blown up by a bomb delivered by a police robot.
The black army veteran portrayed the attack on the white officers as payback for the fatal police shootings of black men in Baton Rouge, Louisiana, and suburban Minneapolis.
Portions of both shootings were videotaped and broadcast nationwide, leading to fresh outrage, protests and scores of arrests.
The killings also put the country on edge, heightened racial tensions and pushed the issue of the use of deadly force against black males by white police officers to the forefront.
Mr Obama will seek to bridge those issues with his tribute to the fallen five, who included a former army ranger, a navy veteran and a newlywed starting a second family.
The President, joined by his wife, Michelle, and Vice President Joe Biden and his wife, Jill, will also meet privately with the dead officers' families as well as the injured to convey the support and gratitude for their service and sacrifice that has been expressed around the country.
At least nine other officers and two civilians were injured in the attack.
Former president George W Bush and his wife, Laura, will also attend. Mr Bush, who settled in Dallas after leaving office in 2009, will also speak at the service.
White House spokesman Josh Earnest said Mr Obama recognises that people across the US join Dallas in grieving over the recent, troubling events.
"The President is hoping to offer some measure of comfort," Mr Earnest said.
Mr Obama and Mr Biden met police chiefs, sheriffs and rank-and-file officers on Monday to discuss adopting a series of reforms that were drafted by a White House taskforce on policing, as well as how to restore trust between police officers and the communities they are sworn to serve and protect.
Mr Obama is planning a meeting tomorrow with a broader group that includes law enforcement, activists and academics.