They said that's affecting business and residential internet, as well as video and voice customers.
"We are aware and working to restore services as quickly as possible", the ComcastCares Twitter account told customers.
N.Korea Could Boost Economy of Unified Korea
USA will "constantly reassess" progress in the negotiations to determine if they should continue, CNN reported. "In other words, there is no 'deal, '" he said.
Comcast later released a statement indicating services were being restored: "We identified two, separate and unrelated fiber cuts to our network backbone providers".
Comcast residential and business customers from coast to coast are experiencing a loss of service on Friday afternoon.
The company, based in Philaedelphia, is reportedly the second largest broadcasting and cable television firm in the world.
Comcast reports 'nationwide service interruption'
This reporter's internet is partially affected, with some websites failing to load but others functioning normally. The company directed customers to try its status center online and said crews were working to restore service .
If you are on Xbox Live and having troubles with the party system, that is probably due to the Comcast outage. The company has responded on social media that service will be restored.
The No. 1 cable provider is dealing with nationwide outages of its broadband, TV and voice services.
United States envoy urges Pakistan to stop protecting terrorists
She said Pakistan has been cooperating with the United States, but Washington can not accept any government protecting terrorists. Nikki Haley is the first Indian-American to serve in a Cabinet-level position in any United States presidential administration.