Washington, Nov 4 (IANS): US President Donald Trump on Friday pressured the Justice Department and the FBI to investigate Hillary Clinton, ticking through a slew of issues involving the 2016 Democratic presidential nominee and her party, and urging law enforcement to "do what is right and proper".

In a Thursday radio interview, Trump said "the saddest thing" about being President was that he can't give orders to the Justice Department or Federal Bureau of Investigation.

The President said he was "very frustrated" that he could not be involved with those agencies and said it was "very discouraging to me" that they were not "going after Hillary Clinton", the Washington Post reported.

"Hopefully they are doing something and at some point, maybe we are going to all have it out," Trump said on "The Larry O'Connor Show".

As he departed the White House on Friday morning for an 12-day trip to Asia, Trump told reporters: "A lot of people are disappointed in the Justice Department, including me."

In a series of tweets, Trump claimed there was mounting public pressure for the Justice Department to investigate Clinton.

Trump suggested law enforcement reopen its probe of the deleted emails from Clinton's private server while she was Secretary of State, as well as a Russian uranium sale and the international business of Democratic super-lobbyist Tony Podesta.

Trump also raised the Clinton campaign's joint fundraising agreement with the Democratic National Committee that effectively gave her control over the party's finances, strategy and staffing before the primaries began.

The details were outlined in a new book by former DNC interim chair Donna Brazile.

Trump tweeted: "Everybody is asking why the Justice Department (and FBI) isn't looking into all of the dishonesty going on with Crooked Hillary & the Dems."

"New Donna B book says she paid for and stole the Dem Primary. What about the deleted E-mails, Uranium, Podesta, the Server, plus, plus.

"... People are angry. At some point the Justice Department, and the FBI, must do what is right and proper. The American public deserves it!"

In a fourth tweet, Trump alleged that "the real story on Collusion" is the fundraising agreement noted in Brazile's book.

The President appeared to be conflating collusion with a foreign government, which is a subject of Mueller's Russia investigation, with the financial arrangement Clinton's campaign made with the DNC, the Post reported.

And in a fifth tweet, Trump invoked Senator Elizabeth Warren, who said that she believed the Democratic primaries were rigged in Clinton's favour.

"Pocahontas (Warren) just stated that the Democrats, lead by the legendary Crooked Hillary Clinton, rigged the Primaries! Lets go FBI & Justice Dept."

A Justice Department spokesman declined to comment on the issue.