Donald Trump has attacked the FBI and investigators probing alleged Russian election meddling in a weekend tweet-storm, saying an excessive focus on Russia distracted investigators from preventing the deadly school shooting in Florida.

Key points: Mr Trump accuses Barack Obama of failing to stop Russian election interference

Mr Trump accuses Barack Obama of failing to stop Russian election interference Rival says the Russia probe and the school shooting shouldn't be linked

Rival says the Russia probe and the school shooting shouldn't be linked Mr Trump calls Russia probe investigator a leaking "monster"

In a series of tweets sent from his Mar-a-Lago estate in Florida, the United States President said congressional investigations and political "hatred" showed Russia had succeeded in sowing "discord, disruption and chaos" within the US.

He also accused former president Barack Obama of failing to do enough to stop Russian election interference.

In a tweet on Saturday night (local time), Mr Trump criticised the FBI for missing warning signs in the case of Nikolas Cruz, 19, who is charged with killing 17 people at Marjory Stoneman Douglas High School in Parkland, Florida.

The FBI acknowledged on Friday that it failed to investigate a warning that Mr Cruz possessed a gun and the desire to kill.

Loading

Mr Trump also took exception to his National Security Adviser HR McMaster saying on the weekend the evidence of Russian meddling was beyond dispute.

Loading

Adam Schiff, the ranking Democrat on the House intelligence committee that is investigating Russia's actions, also came into the President's firing line, being labelled a leaking "monster".

Loading

Mr Schiff, speaking on CNN's State of the Union, said details of the Mueller indictment provided "overwhelming and unequivocal" evidence of the threat from Russian interference.

He said the indictments countered Mr Trump's frequent comments that the Russia investigation is a "hoax".

"This is a president who claims vindication anytime someone sneezes," Mr Schiff said.

Loading

Mr Trump also said the handling of the Russia probe was playing into Moscow's hands.

Loading

After a six-hour break from the social media platform, Mr Trump returned seemingly in a more genial mood, urging followers to "enjoy the race" ahead of the Daytona 500 in Florida.

Loading

The tweets follow the announcement on Friday that special counsel Robert Mueller had charged 13 Russians and three Russian companies with a conspiracy to tamper in the 2016 US election.

The indictment said Russians adopted false online personas to push divisive messages and staged political rallies while posing as Americans, among other charges.

Russia and shooting 'two separate issues'

Several politicians rejected Mr Trump's linking of the FBI's missteps in preventing the shooting to the Russia probe.

"So many folks in the FBI are doing all that they can to keep us safe. The reality of it is, is that they are two separate issues," Republican senator Tim Scott said on CBS's Face the Nation program.

After Mr Mueller's indictment was made public, Mr Trump said it backed up his assertion that there was no collusion between his campaign and Russia.

The indictment did not address whether anyone from the Trump campaign coordinated or worked with Russians. Mr Mueller's broader probe is ongoing.

"It wasn't designed to be able to clear everything on the investigation," Republican senator James Lankford said on the NBC's Meet the Press.

"It was designed to say it was very clear these 13 individuals in this set of companies were trying to interfere in our election," said Mr Lankford, who sits on the Senate Intelligence Committee.

Reuters