An Iranian-linked hacking group is claiming it knocked out AT&T's internet service across parts of Dallas for hours on Monday, but the company says that is not what happened.

Hacker claim vs. cable theft What we know: An Iranian-linked group known as APT Iran claimed responsibility for a multi-hour AT&T internet outage across parts of Texas on Monday.

However, AT&T issued a statement saying it has "no evidence to support that claim." Instead, the company said the outage was caused by an attempted cable theft.