President Obama has offered prayers for the people of Oklahoma, and said the nation will back them as they seek to recover from a devastating tornado that claimed at least two dozen lives.
"As a nation, our full focus right now is on the urgent work of rescue," Obama said at the White House.
The president, who had just received a briefing on recovery efforts, said Oklahoma "will have all the resources they need at their disposal".
Describing the devastation of the storm that ripped through the town of Moore, Obama said "in an instant neighborhoods were destroyed," and "among the victims were young children".
Obama said officials still don't know the full extent of the damage, either in terms on economic losses or total deaths, and the people of Oklahoma face "a long road" to recovery.
The President has also spoken by phone to Oklahoma lawmakers, pledging federal assistance as damaged areas rebuild.
The Pope has also expressed sympathy for the victims of the devastating tornado.
Pope Francis sent out a tweet saying: "I am close to the families of all who died in the Oklahoma tornado, especially those who lost young children. Join me in praying for them."
The state medical examiner's office has revised the death toll to 24 people, including at least seven children.
Earlier reports suggested the death toll was 51 but spokeswoman Amy Elliot said she believes some victims were counted twice in the early chaos of the storm.
The strength of the storm wiped out neighbourhoods.
Pastor Ben Glover, from the Oakcrest Church of Christ in Oklahoma City, had just minutes to get home to his daughter.
He said it was desperate: "The rain stopped, the wind stopped and actually the sun came out and those are never good sings because that means you are very close.
"So I just raced in, grabbed her and put her in the car and we went north and west away from the Tornado. I knew if I could get there ahead of time we probably had time to get out of there."
Pastor Glover also tells Premier's Des Busteed what they've been doing to help the local community:
The twister, around two miles long, carried winds of up to 200 miles-per-hour. It destroyed everything in its path, including the Plaza Elementary School.
Mayor of Moore city, Glenn Lewis said there wasn't anywhere to move the children to: "The schools, basically, are fairly well hardened and they usually get under their desks in a safe room and this is unfortunately one of the older schools in the city and the structure was not built as well as it should have been."
Briarwood Elementary school was also damaged, and teachers were later seen leading pupils out to safety.
More than 120 people are being treated at hospitals and President Obama has declared it a major disaster.
The Salvation Army USA, the Billy Graham Evangelistic Association, and local churches are all providing support after the twister caused devastation.
The Salvation Army is on the ground in Moore, an area worse hit, with canteens and volunteers serving the emergency services and those affected.
Major Steve Morris, Arkansas-Oklahoma Divisional Commander has been driving around the affected area.
"The devastation is far reaching both in human life, property and livestock loss.
"The Salvation Army is honoured to serve and provide sustenance to first responders involved in search and rescue, coordination efforts and more.
"And, of course, all survivors will be provided spiritual and emotional care."
Trained chaplains with the Billy Graham Rapid Response Team are also in Moore providing assistance.
Its International Director Jack Munday said: "Our hearts are breaking for all of those in the path of this horrific tornado.
"Words can't do justice to the pain that is being experienced in and around Moore.
"Please pray continuously for all of those who lost loved ones, and for those who may still be trapped amidst the rubble."
The Queen has said she's "deeply saddened" by the loss of life and devastation caused by the tornado.
She's sent her deepest sympathies to all those whose lives have been affected.
In the General Assembly of the Church of Scotland meeting today in Edinburgh, prayers were offered by the Moderator the Right Revd Lorna Hood for victims.
She asked that God would comfort grieving families and work through the responding agencies to "bring that touch, that healing to wipe away their tears, to bring that peace and most of all to know that you are with them and you will be close".