WASHINGTON, May 31 (Xinhua) -- A number of popular landmarks of the U.S. capital around the National Mall in central Washington D.C. were defaced with graffiti amid nationwide protests and unrest over the death of George Floyd, an unarmed black man in Minneapolis police custody, the authorities said Sunday.

"In the wake of last night's demonstrations, there are numerous instances of vandalism to sites around the National Mall," the National Park Service for the National Mall said in a tweet with photos of defaced monuments on Sunday.

The sentence "Do black Vets count?" appeared to be spray-painted across part of the National Mall World War II Memorial and the words "Yall not tired yet?" were spray-painted at the Lincoln Memorial.

"For generations the Mall has been our nation's premier civic gathering space for non-violent demonstrations, and we ask individuals to carry on that tradition," the service said on Twitter.

DC Chief of Police Peter Newsham said on Sunday that the Metropolitan Police Department had arrested 17 people Saturday night and that 11 police officers were injured during the protests.

None of the officers sustained life-threatening injuries, though one officer is undergoing surgery for multiple compound fractures to his leg after a protester threw a rock at him, according to a CNN report.

Floyd, aged 46, died on May 25 after Derek Chauvin, a white police officer, held him down with a knee on his neck though he repeatedly pleaded, "I can't breathe," and "please, I can't breathe." Chauvin was arrested and charged with three-degree murder and manslaughter earlier on Friday.

Floyd's plea before his death evoked African Americans' painful memories. In 2014, a cellphone recorded an unarmed black man, Eric Garner, repeatedly saying "I can't breathe" when a New York officer held him in a chokehold before his death in police custody. Since then, the plea has become a rallying cry at demonstrations against police misconduct across the country.