The Democratic Party has sued President Donald Trump's campaign, his son, his son-in-law, the Russian Federation and WikiLeaks, saying they conspired to help Mr Trump win the 2016 presidential election.

Key points: The party alleges that Mr Trump's campaign "gleefully welcomed Russia's help" in election

The party alleges that Mr Trump's campaign "gleefully welcomed Russia's help" in election The lawsuit seeks unspecified damages

The lawsuit seeks unspecified damages The claims raised are already being investigated by Robert Mueller

The party alleges in the federal lawsuit that top Trump campaign officials conspired with the Russian government and its military spy agency to hurt Democratic presidential nominee Hillary Clinton and tilt the election to Mr Trump by hacking Democratic Party computers.

The lawsuit also names Donald Trump Jr, Trump associate Roger Stone and Mr Trump's son-in-law Jared Kushner as defendants.

The lawsuit alleges that Mr Trump's campaign "gleefully welcomed Russia's help" in the 2016 election.

The Democrats allege the Trump campaign conspired with the Russian government to disrupt the Clinton campaign. ( Reuters: Carlos Barria/Jonathan Ernst, file )

The Democratic National Committee (DNC) filed the lawsuit on Friday in the federal court in Manhattan.

It seeks unspecified damages and an order to prevent further interference with DNC computer systems.

The White House did not immediately respond to requests for comment.

Mr Trump has repeatedly denied his campaign colluded with Russia.

Russia has also denied meddling in the election.

The Republican National Committee, the Trump campaign, Trump campaign manager Michael Glassner, WikiLeaks, Mr Stone and attorneys for Mr Trump Jr., former campaign chairman Paul Manafort, Manafort associate Rick Gates and former campaign aide George Papadopoulous also did not immediately respond to requests for comment.

Four US intelligence agencies reported last year that Russia sponsored the hacking of Democratic Party groups and other actions during the 2016 campaign.

Part of the effort was to benefit Mr Trump over Ms Clinton, the agencies said.

The DNC blames Russia for breaches of its computer systems in 2015 and the first half of 2016.

Hackers disseminated internal communications of party officials as the Democratic nominating convention began and WikiLeaks released thousands of emails, some of which were embarrassing for the Clinton campaign and were intended to stoke conflicts among the party's supporters.

Most of the accusations appeared to be based on news reports and publicly available legal documents and offered little new information about alleged collusion with Moscow.

The lawsuit, should it go forward, would likely keep the spotlight on the issue of Russian election interference and possible collusion by the Trump campaign.

Both are already being investigated by Special Counsel Robert Mueller.

Through the process of legal discovery, lawyers for the Democratic Party could force the defendants to produce documents bearing on the collusion issue.

Reuters/AP