Four officers with the St. Louis Police Department were wounded by gunfire amid ongoing violent protests Monday night.

According to KMOV-TV , all four officers reportedly suffered non-life-threatening injuries and were transported to a nearby hospital for treatment.

Speaking to reporters, Police Chief John Hayden said that the officers were standing near a line and "all of a sudden they felt pain."

He continued, "They were just standing there. So some coward fired shots at officers and now we have four in the hospital... and thank God they’re alive. Can we make some sense out of this? ... This is horrible."

Hayden added, "We had officers who had gas poured on them. And we’re trying to figure out what is going on. How could this be? Mr. Floyd was killed somewhere else, and they’re tearing up cities all across the country."

At least 40 cities have imposed curfews and National Guard members have been activated in 15 states as protesters turn into rioters, looting stores and burning buildings and cars.

The total number of officers nationwide to be injured in the weeklong rioting remains unclear, and the destruction of property is estimated to be multiple millions of dollars. An untold number of rioters have been arrested for failing to comply with commands to disperse, and numerous otherwise-peaceful protesters have been injured by those who have turned violent during public gatherings.