The Federal Bureau of Investigation said on Monday that it was investigating the nature and scope of a cyber intrusion at the Democratic National Committee disclosed last month.

"A compromise of this nature is something we take very seriously, and the FBI will continue to investigate and hold accountable those who pose a threat in cyberspace," the FBI said in a statement.

The top Democrat on the U.S. House of Representatives Intelligence Committee said on Monday the panel had been briefed on the reported hack into the Democratic National Committee email system and would seek information as to the origin of any attack and possible connection to Russia or other countries.

"If the hack is linked to Russian actors, it would not be the first time cyber intrusions linked to the Kremlin and its supporters have sought to influence the political process in other countries," U.S. Representative Adam Schiff said in a statement.