A significant number of Comcast customers were without broadband, phone, and internet service for several hours Tuesday morning because of what the company called a “hardware issue.”

“Early yesterday morning, our engineers detected a hardware issue that impacted voice, video and Internet services for a subset of customers across the country for several hours,” Comcast said, in a statement. “During this time, customers also may have had difficulty reaching us by phone. Our engineers quickly identified and resolved the issue, and services have returned to normal. We appreciate our customers’ patience as we worked to fix this and are sorry that we inconvenienced them.”

Major parts of Boston, San Francisco, Seattle, and Portland were without service until 10:30am ET.