Officials in the U.S. are stepping up security at some arenas following the deadly attack Monday on a concert venue in Manchester, England.

CNN reported that officials are revising their protocols, adding officers and deploying dogs that can sniff out explosives.

Officials declined to give specific details about the changes in security, however, according to CNN.

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Various concert venues across the country, including the Allstate Arena near Chicago, reportedly have made some changes to their security.

At the Illinois venue, they stepped up security presence outside with "a few more visible uniformed Rosemont police officers," said Pat Nagle, the arena's executive director.

Other venues, including those in Texas and California, also upped their security in preparation for concerts, according to the news network.

The moves come after the attack in Manchester killed at least 22 people and wounded dozens more.

On Tuesday, the U.K. raised its threat level to "critical" and British Prime Minister Theresa May warned a "further attack may be imminent."

The Islamic State in Iraq and Syria claimed responsibility for the incident.

The Department of Homeland Security said late Monday after the attack that there was no credible threat to U.S. music venues, but warned there may be increased security around public places and events.