US visitor visa application with UK Visa

Hey everyone. I have a UK visitor visa valid until next year. I want to apply for a US visitor visa at the Embassy here in the UK. I’m not sure about the rules - is that feasible or possible. I can’t apply in my home country cause the embassy is temporarily closed. So my question is does the visitor visa allow that. I already posted this in r/ukvisa and it was removed so I hope here is appropriate. Please advice.