The United States and Iran are set to hold indirect talks in Switzerland on Thursday aiming to strike a deal to avert fresh conflict and bring an end to weeks of threats.

The new round of negotiations in Geneva comes after the US carried out a massive military build-up in the region and President Donald Trump repeatedly threatened to strike Iran if a deal is not reached.

In his State of the Union address on Tuesday, Trump accused Iran of "pursuing sinister nuclear ambitions".

He also claimed Tehran had "already developed missiles that can threaten Europe and our bases overseas, and they're working to build missiles that will soon reach the United States of America".

The Iranian foreign ministry called these claims "big lies".