Former Donald Trump staffers surrender to the FBI following Russia investigation.

Two of US President Donald Trump’s former staffers have surrendered to the FBI, following the investigation into possible coordination between Russia and Trump’s 2016 election effort.

Former campaign chairman, Paul Manafort, and a former Manafort business associate, Rick Gates, have been indicted on felony charges of conspiracy against the US; acting as an unregistered foreign agent; and several other financial counts involving tens of millions of dollars routed through offshore accounts.

This comes at the same time another Trump aide, George Papadopolous, on Monday pleaded guilty to lying to the FBI about his contacts with a Russian national during his time on the Trump campaign, AAP reports.

Listen: Mia Freedman and Amelia Lester debrief on the latest on Planet Trump, including his horrendous treatment of a war widow. Post continues after audio. 

Although the latest indictment doesn’t reference the Trump campaign or make any allegations about co-ordination to influence the outcome of the election in Trump’s favour, it does allege a criminal conspiracy was continuing through February 2017.

Both Manafort and Gates are accused of funnelling tens of millions of dollars in payments through foreign companies and bank accounts as part of their political work in Ukraine.

In total, more than $US75 million flowed through the offshore accounts. Manafort is accused of laundering more than $US18 million, according to the indictment.

It's alleged the pair orchestrated a nearly decade-long conspiracy to covertly work for Ukrainian interests and launder millions of dollars, AAP reports.

Manafort and Gates have previously denied any wrongdoing.

The indictments are the first from special counsel Robert Mueller's sprawling investigation. And pose the threat of a years-long prison sentence for the man who once led the president's campaign, AAP reports.

President Trump has responded to the indictments, saying the alleged misdeeds were "years ago" and asserted there was "NO COLLUSION!" between his campaign and the Russian government.

The president also asked on Twitter why "Crooked Hillary & Dems" aren't the focus of the probe.

Trump and the White House insist there was no collusion between his presidential campaign and Russia. Both have pointed a finger at Clinton and have suggested that the real story of collusion with Russia is the sale of uranium to Moscow when Clinton was secretary of state.

US intelligence agencies have concluded that Russia interfered with the election to benefit Trump, a finding that Trump has not fully accepted. Mueller and congress are looking into allegations of ties between Trump associates and Russia.

More to come, we are sure.