Seven people were injured, including one critically, and two people remain missing after an explosion rocked downtown Youngstown, Ohio, Tuesday, officials said.

The explosion occurred near Central Square Tuesday afternoon, police said, urging people to avoid the area.

It is unclear what caused the explosion, which impacted a building that contains a Chase bank and apartments, authorities said.

Youngstown Fire Chief Barry Finley had initially characterized the incident as a natural gas explosion, but later said crews were working to determine if there was a gas leak.

“All I know for sure is that there was an explosion,” Finley told…