Islamic State Group Claims Responsibility for Deadly Manchester Blast |

The United States' top intelligence official says the U.S. government has not yet verified that the Islamic State group is responsible for the Manchester attack.

Dan Coats, the director of national intelligence, told Congress that the extremist group frequently claims responsibility for terror attacks.

The Islamic State group says one of its members planted bomb in crowds in the suicide attack at an Ariana Grande show Monday night that left 22 people dead. The group warned in a statement on social media that more attacks are to come.

Testifying Tuesday before the Senate Armed Services Committee, Coats says though he was aware of the IS claim of responsibility, U.S. authorities hadn't yet verified that.

He says the Manchester attack is a reminder the terrorist threat is real. He says, "It's not going away and it needs significant attention."

Manchester Police has confirmed that the attacker was 23-year-old Salman Abedi, who was known to British authorities.

The concert drew a sell-out crowd to Manchester Arena -- about 20,000 people -- and it was just ending.

President Trump addressed what happened while speaking with reporters in Bethlehem during his visit to the Middle East.

After expressing his condolences to the victims of the attack, Trump had harsh words for those responsible for the violence.

"So many young, beautiful, innocent people living and enjoying their lives murdered by evil losers in life. I won't call them monsters because they would like that term. They would think that's a great name. I will call them, from now on, losers because that's what they are. They're losers. You will have more of them. But they're losers, just remember that."

Manchester police's chief constable, Ian Hopkins, said Tuesday that they believe one person carried out the attack.

Greater Manchester Police say roughly 50 people were injured. Officials say children are among the victims.

A shopping mall in the center of the city was evacuated Tuesday morning for a police operation, but there were few details immediately available, and it wasn't clear whether there was a connection to the Monday night attack.

Police sealed entrances to the Arndale Centre shopping mall and closed roads around it, and later confirmed one man had been taken into custody at the mall. They said, however, that the arrest was "not currently believed to connected to last night's attacks."

In a tweet, the Greater Manchester Police said a 23-year-old man was taken into custody in the southern part of the city on Tuesday, and that arrest did appear to be linked to the bombing.

Queen Elizabeth II released a short message, meanwhile, expressing her shock and "deepest sympathy to all who have been affected by this dreadful event and especially to the families and friends of those who have died or were injured."

The Queen praised the emergency services and expressed "admiration for the way the people of Manchester have responded, with humanity and compassion, to this act of barbarity."

British Prime Minister Theresa May says the government is trying to establish "the full details of what is being treated by the police as an appalling terrorist attack." May said her thoughts are with the victims and the families of those who have been affected and that the government is expected to call an emergency cabinet meeting to deal with the incident.

A representative of Grande's US record label says the singer is OK and Grande tweeted hours later: "Broken. From the bottom of my heart, I am so so sorry. I don't have words."

Concert promoters at London's O2 Arena, where Grande is scheduled to perform Thursday and Friday, say they are in contact with the singer's team about her next steps.

"We are shocked and deeply saddened by the terrible tragedy in Manchester. Our thoughts and prayers are with those affected and their families," the arena said in a statement. "We are in contact with the promoters of Ariana Grande's tour and will update as soon as we have further information regarding the planned dates at The O2."

Grande has yet to tell fans whether she will continue her European tour following the deadly blast at her concert in Manchester.

Video from inside the arena showed concertgoers screaming as they made their way out amid a sea of pink balloons.

The Associated Press, CBS News contributed to this story