Donald Trump Jr

Donald Trump Jr, Jared Kushner and Paul Manafort are accused of having links with Russian officials.

Mr Trump and his allies have denied any collusion.

Meanwhile, Mr Trump said he would not have named Jeff Sessions had he known he would recuse himself from the probe.

In an interview with the New York Times, Mr Trump called the attorney general's decision "very unfair".

"Sessions should have never recused himself, and if he was going to recuse himself, he should have told me before he took the job and I would have picked somebody else," Mr Trump said.

Donald Trump Jr tweeted an article written last year, in which Sadiq Khan said terror vigilance had become "part and parcel" of life in a global city.

"You have to be kidding me?!" said Mr Trump, immediately sparking accusations that he was exploiting the tragedy and misrepresenting the mayor's point.

Dozens were hurt in the London attack.

Trying to suggest the US should not accept any refugees, Donald Trump Jr posted an image that asked:

"If I had a bowl of skittles and I told you just three would kill you, would you take a handful?''

"That's our Syrian refugee problem."

He added: "This image says it all. Let's end the politically correct agenda that doesn't put America first."

The food analogy has been used before to imply that, if a few people in a group are bad, it would be dangerous to take a single one in.