Nancy Pelosi, the US House Democratic leader, has said that the recent cyber attacks on Democratic politicians and officials were "broad" and repeated the accusation that Russian authorities were behind behind the breaches that caused controversy and division within the party.

"It is the Russians," Pelosi told reporters at a news conference on Thursday, referring to the recent hacking of the Democratic National Committee's computers.

The cyber attacks, which mainly targeted presidential candidate Hillary Clinton and her allies in the DNC, resulted in a trove of internal emails released by the whistle-blower website WikiLeaks and appeared to show party officials working together to ensure Clinton won the presidential nomination over her rival Bernie Sanders.

READ MORE: Leaked emails appear to show hostility to Sanders

The leaks prompted Debbie Wasserman Schultz to resign as DNC chairwoman and spurred further accusations of election rigging in the Democratic primary.

Pelosi called the cyber attack, made public last month, an "electronic Watergate" akin to the 1972 burglary at Democratic Party headquarters at the Watergate office that brought an end to Richard Nixon's presidency.

"This is a break-in," she said.

Pelosi's comments come on the heels of a New York Times report on Thursday that the cyber attack targeting Democrats was wider than first thought, with more than 100 party officials and groups affected.

"We are assessing the damage," Pelosi told reporters.

The Obama administration has not publicly named Russia as being behind the attack, but investigators have concluded that the attackers were directed by the GRU, Russia's military intelligence service, and the FSB, the civilian espionage agency.

Clinton has repeatedly accused Moscow of being behind the hacking.

READ MORE: US election fraud allegations prompt calls for reform

The cyber attack has prompted the government to "carefully consider" whether the government should step up its protection of the election system by launching greater digital security measures for electronic voting machines, Jeh Johnson the US Department of Homeland Security chief, said.

"We’re actively thinking about the election and cybersecurity right now," he told reporters.

However, some activists accuse Democratic leaders of using Russia as a scapegoat and as a diversion from the political controversy the leaks exposed amid widespread allegations of vote rigging in the Democratic primary.

Shyla Nelson, a cofounder of the civil rights group Election Justice USA, said: "The narrative that somehow 'foreign operatives' would be doing so [hacking] in order to interfere with our national elections is not only unsubstantiated, it's reckless and incendiary.

"Election fraud in 2016 has been, by all verified accounts, an inside job. No tinfoil hats."