A mass “doxing” effort to track down, intimidate and harass people perceived not to have sufficiently mourned the killing of the rightwing activist Charlie Kirk was endorsed on Monday by JD Vance.

The US vice-president guest-hosted Kirk’s podcast on Monday and said that people who “see someone celebrating Charlie’s murder” should “call them out”. He added: “Hell, call their employer. We don’t believe in political violence, but we do believe in civility, and there is no civility in the celebration of political assassination.”