Donald Trump has hailed Billy Graham's 'extraordinary life', praising him as a hero and an 'ambassador of Christ' at a memorial service in the Capitol Rotunda to honour the evangelist following his death aged 99 last week.

Political leaders from both parties gathered on Wednesday to pay their respectsto Graham in the Rotunda, where he was the first private citizen to lie in honour since the civil rights heroine Rosa Parks in 2005.

Trump laid a wreath at the coffin of Billy Graham, who is thought to have preached to more than 210 million people over the course of his life and developed close relationships with presidents since Harry Truman.

'Today, in the centre of this great chamber lies legendary Billy Graham, an ambassador for Christ who reminded the world of the power of prayer and the gift of God's grace,' he said.

Trump said he went to see Billy Graham preach in Madison Square Garden in 1957 where the evangelist addressed more than 2 million people over 16 weeks.

'I remember that, because my father said to me, "Come on, son" – and, by the way, he said, "Come on, mom. Let's go see Billy Graham at Yankee Stadium." And it was something very special.'

He went on: 'Billy Graham carried his message around the world, but his heart, as Franklin will tell you, was always in America. He took his message to the poorest places, to the downtrodden and to the brokenhearted, to inmates in prison, and to the overlooked and the neglected. He felt a great passion for those that were neglected.

'Everywhere he went, Reverend Graham delivered the same beautiful message: God loves you. That was his message. God loves you.

'We can only imagine the number of lives touched by the preaching and the prayers of Billy Graham –- the hearts he changed, the sorrows he eased, and the joy he brought to so many. The testimony is endless.'

By lying in honour at the Rotunda Graham joins a list of just 30 Americans including former presidents, military commanders, law enforcement officers killed in the line of duty and the remains of unidentified soldiers from several of the nation's wars.

Graham's body will remain there until Thursday where it will travel back to Charlotte ahead of his funeral tomorrow, expected to be attended by around 2,300 people including Donald Trump and a number of former presidents.