Pornhub queen Mia Khalifia has weighed in on the riots in Baltimore, urging violent protesters not to touch the city's iconic Old Bay garage.

The 22-year-old adult film star, who grew up in Maryland, took to social media to tell those involved in the ongoing unrest not to dare touch "our national monument".

Baltimore first descended into anarchy on 27 April, on the same day as the funeral of 25-year-old Freddie Gray, who died from injuries sustained while in police custody. Although it's not clear whether Khalifa's comment was meant as a joke, it provoked a strong response from the online community.

Khalifa, who shot to fame after provoking outrage within the Middle East following her porn debut in October 2014, is the latest star to speak out on social media with messages of support, caution and peace.

David Simon, the creator of The Wire TV series based on Baltimore Police Department shot in and around the Maryland city, slammed the riots and violence as "selfishness".

"The anger and the selfishness and the brutality of those claiming the right to violence in Freddie Gray's name needs to cease," he wrote on his blogpost entitled The Audacity of Despair. "If you can't seek redress and demand reform without a brick in your hand, you risk losing this moment for all of us in Baltimore. Turn around. Go home. Please."

Reality star Khloe Kardashian encouraged fans to pray for Baltimore insisting that "violence wasn't the answer".

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A photo posted by Khloé (@khloekardashian) on

And John Legend made sure to inform his fans about what was happening in the street of Baltimore by tweeting an article about the protests.

Meanwhile, Governor Larry Hogan has declared a state of emergency and the city mayor Stephanie Rawling-Blake has placed the city under a week-long 10pm-5am curfew in as bid to curb the violence.