Thousands of miles from his Washington impeachment trial, President Donald Trump took centre stage at Davos to tout the success of the US economy, while criticising the US Federal Reserve on Tuesday.

Greta Thunberg refused to answer a question about dealing with haters at the World Economic Forum's (WEF) annual meeting, also known as Davos.

US President Donald Trump branded his impeachment trial a "hoax" in the Swiss resort of Davos on Tuesday, hours before senators were to start debating a push to remove him from office.