Donald Trump revived questions of US President Barack Obama's religion, saying the US President went to a mosque in Baltimore because "maybe he feels comfortable there". "I think that we can go to lots of places. I don't know, maybe he feels comfortable there," Trump said, adding, "We have a lot of problems in this country. There are a lot of places he can go and he chose a mosque. I saw that just a little while ago. So that's his decision, it's fine."