Hampton later deleted the tweets and described them as "error-ridden". However, she confirmed to the Guardian that Bey and Jay-Z helped to bail protesters caught up in the demonstrations.

Protests spread last year after a white police officer shot dead African American teenager Michael Brown in the St Louis suburb of Ferguson. Last month, major and sometimes violent demonstrations again broke out in Baltimore after the death of another black man, 25-year-old Freddie Gray, whose spine was nearly severed in police custody.

Video footage filmed by a passerby showed a visibly distressed Gray being handcuffed on the ground pushed into the back of the van.

Beyonce and Jay-Z are one of the richest couples in America, with an estimated net worth of $1 billion (£640 million).

Bey recently added her voice to the ongoing debate borne out of the civil unrest, in a series of Instagram posts three weeks ago (above). The first showed a TIME video clip juxtaposing the infamous Baltimore riots of 1968, which raged for more than a week following the assassination of Dr. Martin Luther King, with riots of last month. The second post was an image of a man wearing a black and white American flag with Freddie Grey’s name written on it.

According to AFP news agency, Bey and Jay-Z had been criticised by some activists for merely paying lip service to the cause. Hampton's tweets were likely an attempt to deflect that criticism.

Before she deleted her tweets, Hampton noted that the couple's contribution was important because - she claims - authorities are trying to quash protests with exorbitant bail conditions.

"They're waging war on black resistance in a multitude of ways, many of them financially," she said. "Protest is literally punished with tariffs. When they fine and arrest people for protesting, more opportunities for exploitation by the state are possible with each encounter."

Beyonce and Jay-Z 'gave thousands of dollars' to free protesters in Baltimore and Ferguson, claims activist