Prayers are being said after an attempt on the life of Donald Trump at a rally on Saturday that left the former US president injured and a spectator dead. 

The Republican nominee was bundled away by Secret Service agents after narrowly escaping death with a gunshot wound to his ear. Footage from the scene of the rally in Butler, Pennsylvania, showed Trump with blood on his face.

The gunman was shot and killed by the Secret Service at the scene. He has been named by the FBI as 20-year-old Thomas Matthew Crooks. 

President Joe Biden said he had spoken to Trump as condemned the shooting.

"There is no place for this kind of violence," he said. "It's sick, it's sick."

He added, "We cannot allow for this to be happening. We cannot be like this." 

Vice-President Kamala Harris said she was "relieved that he is not seriously injured". 

"We are praying for him, his family, and all those who have been injured and impacted by this senseless shooting," she said. 

Evangelist Franklin Graham, who often spoke in support of Trump during his presidency, asked his 10 million Facebook followers to join him in praying for the presidential hopeful. 

"I thank God that former President Donald J. Trump is alive," he said. 

"Our prayers are also with the others injured at the rally today and the family of the individual who was killed."

The gunman is reported to have fired from a rooftop that was outside the security parameter.

Trump, 78, was defiant in the moments after the shooting, raising his fist in the air and mouthing the word 'fight' as he was ushered off the stage by Secret Service agents. 

He has left hospital after being grazed in the ear. 

In a statement, Trump said, "I want to thank the United States Secret Service, and all of law enforcement, for their rapid response on the shooting that just took place in Butler, Pennsylvania. Most importantly, I want to extend my condolences to the family of the person at the rally who was killed, and also to the family of another person that was badly injured. It is incredible that such an act can take place in our country."

He said the bullet had pierced the upper part of his right ear.

"I knew immediately that something was wrong in that I heard a whizzing sound, shots, and immediately felt the bullet ripping through the skin. Much bleeding took place, so I realised then what was happening. God bless America!" he said.

Christian leaders are asking for prayers and appealing for peace after the assassination attempt. 

Pastor Ed Young said, "We pray for our country. No matter your political leanings or beliefs, we do not resolve our differences in America with acts of violence. We pray for peace and protection over our nation.

"God Bless America. We earnestly pray this nation would turn back to you Lord, your truth, and your leadership.

"Please pray for the family of the innocent bystander who was killed and others injured."

Harvest pastor Greg Laurie said it was tragic that a life had been lost in the shooting. 

"It's time for us as a nation to pray, regardless of our political affiliation. God spared Donald Trump today," he said.