US President Donald Trump has warned Minneapolis Mayor Jacob Frey he is "playing with fire" after the Democratic leader reiterated his city would not ‍help federal agents enforce immigration law. Amid the mixed signals from the White House, tensions remained high in Minneapolis, where observers and activists say immigration raids had not slacked but appeared ​to be more targeted. The city has been convulsed by unrest, including confrontations between protesters and immigration agents, after two US citizens were shot dead by federal agents, including Saturday's killing of nurse Alex Pretti. US Attorney General Pam Bondi said on social media ⁠federal agents had arrested 16 people in Minnesota for allegedly assaulting, resisting or impeding federal law enforcement, and lawlessness would not be tolerated. But on social media on Wednesday, Trump faulted Frey for saying the city would not enforce immigration laws.