Donald Trump condemned the killing of five Dallas police officers as "an attack on our country" and said Friday that racial tensions in America were deteriorating.
"We must restore law and order," the Republican presidential candidate said in a statement. "We must restore the confidence of our people to be safe and secure in their homes and on the street. The senseless, tragic deaths of two motorists in Louisiana and Minnesota reminds us how much more needs to be done."
The shooting of 12 officers in Dallas on Thursday night during a protest against police killings of African-Americans in Louisiana and Minnesota came 10 days before the start of the Republican National Convention in Cleveland.
Months of violent, racially charged protests at Trump rallies across the nation have heightened concerns of potential unrest at the Cleveland gathering, where Trump expects to formally accept his party's presidential nomination.
In the aftermath of the Dallas shootings, Trump canceled his scheduled campaign stops Friday in Miami with his former GOP opponents Chris Christie and Marco Rubio. Moments earlier, Trump's Democratic rival, Hillary Clinton, had scratched her scheduled Pennsylvania campaign event Friday with Vice President Joe Biden.
"Our nation has become too divided," said Trump, whose comments on Mexican immigrants, Muslims and other groups have sparked frequent charges of bigotry.
"Too many Americans feel like they've lost hope. Crime is harming too many citizens. Racial tensions have gotten worse, not better. This isn't the American dream we all want for our children.
"This is a time, perhaps more than ever, for strong leadership, love and compassion. We will pull through these tragedies."
Trump's response to the Dallas shootings was relatively measured for the novice, self-styled candidate whose spontaneous reactions to world events have repeatedly caused him political harm.
He was widely condemned after the killing of 49 people in an Orlando nightclub last month for saying on Twitter that he appreciated "the congrats for being right on radical Islamic terrorism, I don't want congrats, I want toughness & vigilance."
