Nigeria's army have tweeted a video of US President Donald Trump, in which he says soldiers can use force against migrants throwing stones, to justify opening fire on a Shia group this week, reports AFP news agency.

Nigeria's defence spokesman John Agim told AFP that the army posted the video in reaction to an Amnesty International report accusing the army of using weapons against Shia protesters.

"Not only did they use stones but they were carrying petrol bombs, machetes and knives, so yes, we consider them as being armed".

"We intervened only because the IMN [Islamic Movement of Nigeria] members are trying to harm our people, they are always meeting us... at security check points and trying to provoke us, they even burned a police vehicle."

The army admits that three people were killed in clashes in Abuja on Monday, but the IMN says that dozens died.

They were demanding the release of their leader Ibraheem Zakzaky who has been in custody for 34 months.

In the video Mr Trump was referring to Central American migrants attempting to cross the border illegally.

"We're not going to put up with that. They want to throw rocks at our military, our military fights back," he said on Thursday.