UK Prime Minster Boris Johnson says terror incident 'highly likely' after taxi explosion

British Prime Minister Boris Johnson said Monday that another terror attack is "highly likely," a day after a taxi exploded outside a Liverpool hospital that killed the suspected attacker and injured another.

"What yesterday showed above all is that the British people will never be cowed by terrorism, we will never give in to those who seek to divide us with senseless acts of violence," Johnson said. "And our freedoms and our way of life will always prevail."

On Sunday, authorities said four men, who range in ages from 21 to 29, had been arrested under terrorism laws.