US Deputy Attorney General Rod Rosenstein has said he is resigning from his post. He appointed a special counsel in 2017 to investigate links between President Donald Trump's campaign and Russia in the 2016 election, a move which drew criticism from the Trump administration.

Rosenstein submitted a letter of resignation to Trump on Monday saying he will resign on May 11. Deputy Transportation Secretary Jeffrey Rosen has been nominated to replace him.

Rosenstein's departure was not surprise. The Trump administration announced a plan in February to replace him.

Trump was reported to have been frustrated with Rosenstein over his appointment of Special Counsel Robert Mueller to investigate alleged collusion between the Trump election campaign and Russia.

In a report released earlier this month, Mueller said he did not find evidence of collusion. But he did not determine whether or not Trump obstructed justice.

Political observers say after leaving his post, Rosenstein is likely to testify in the House of Representatives regarding the investigation.

NHK