CHARLESTON, W.Va. (AP) — Phone service was knocked out to emergency call centers for several hours in numerous West Virginia counties on Tuesday, officials said.

Residents in some counties were advised to use alternative business numbers to call during the 911 outage.

Frontier Communications spokesperson Chrissy Murray said its fiber optic lines experienced two cuts in northern West Virginia, one involving copper vandalism and the other due to damage related to a winter storm.

“The combination of the cuts is what caused the 911 service issue but we worked quickly to restore so that all of our customers had access to emergency services,” Murray said in a statement.

Frontier is planning to offer up to $5,000 for information leading to the arrest and conviction of those involved in the copper theft, Murray said, adding that tips should be called in to Frontier and local law enforcement.

While 911 calls were going through Tuesday evening in Kanawha County in the state capital of Charleston, the county sheriff’s office said other phone issues remained unresolved. The problem typically involved calls between Frontier landlines and another carrier’s cell phones. Some callers were experiencing busy signals or no response when dialing the sheriff’s office and other places, the office said in a news release.

The office advised callers to reach it using a landline until the issue is resolved.