US Attorney General Jeff Sessions has responded to Donald Trump's latest attack on him by insisting that the justice department he heads will not bend to political pressure.

The apparent rebuke of Mr Trump came after the president said Mr Sessions was not in control of his department.

Mr Trump has been vociferous in his criticism of the Department of Justice.

He has been particularly riled by its handling of the inquiry into Russian interference in the 2016 election.

Mr Sessions, an early supporter of Mr Trump's campaign, has stepped aside from that inquiry to avoid a potential conflict of interest and handed control to his deputy, Rod Rosenstein.

That decision by Mr Sessions, and the ongoing progress of the inquiry under special counsel Robert Mueller - which is also reportedly now looking into whether Mr Trump has attempted to obstruct justice - have provoked frequent outbursts from the president, both in person and on his Twitter feed.

The president remains insistent that there was no collusion between his campaign and the Russian government, and denies he has attempted to obstruct justice.

Impeach me and the market crashes - Trump

After the latest exchanges, two key Republican senators signalled that they would support Mr Trump if he were to fire Mr Sessions after the November mid-term elections.

However, other Republicans told Politico they thought this would be a bad move and said they were standing by the attorney general.

What did Sessions say?

"I took control of the Department of Justice the day I was sworn in," the attorney general said in a statement.

"While I am attorney general, the actions of the Department of Justice will not be improperly influenced by political considerations.

"I demand the highest standards, and where they are not met, I take action."

He added: "No nation has a more talented, more dedicated group of law enforcement investigators and prosecutors than the United States.

"I am proud to serve with them and proud of the work we have done in successfully advancing the rule of law."

Previously, Mr Sessions had been largely non-committal following criticism of him by the president, who appears to believe that Mr Sessions should have shown him greater loyalty instead of recusing himself from the Russia inquiry.

What did Trump say about Sessions?

In an earlier interview with the Fox and Friends programme, Mr Trump said: "I put in an attorney general that never took control of the justice department. Jeff Sessions never took control of the justice department and it's a sort of an incredible thing."

Turning to the Russia inquiry, the president said: "Jeff Sessions recused himself, which he shouldn't have done. Or he should have told me [before I appointed him].

"Even my enemies say that Jeff Sessions should have told you that he was going to recuse himself, and then you wouldn't have put him in. He took the job and then he said I'm going to recuse myself. I said: 'What kind of a man is this?'

"You know the only reason I gave him the job? Because I felt loyalty, he was an original supporter. He was on the campaign. He knows there was no collusion."

A formidable enemy

By Tara McKelvey, White House reporter

Jeff Sessions was originally brought into the Trump campaign because of his hardline views on immigration.

A stubborn man, Mr Sessions fought for decades for anti-immigration policies. Still, he has a gentle manner. I've seen him greeting colleagues with a shy smile at White House events.

Mr Trump prides himself on never giving up, and he admires grit and determination in others - and found those traits in Mr Sessions.

But now he is driving President Trump crazy. Mr Sessions is just as determined as Mr Trump is - and also refuses to back down. Only Mr Sessions is guided by a set of bedrock conservative principles, rather than the egotism and quicksilver impulses that fuel Mr Trump's tweets and, increasingly, his TV interviews.

For these reasons Mr Sessions is a formidable enemy, and the battle between these two men could be long.