A woman, who tried to ram through a White House barricade then led police on a chase towards the US Capitol building, has been pronounced dead, an official said.
More top news
A suspected drunk driver ploughed into a crowd during Mardi Gras celebrations in the southern US city.
The singer had been tweeting in support of migrants when she was bombarded with abusive messages.
Ministers are reportedly considering plans in a bid to lower inward migration.