US President Donald Trump said on Monday that he would be involved "indirectly" in talks between Iran and the US over Tehran's nuclear programme set to begin on Tuesday in Geneva, adding he believed Tehran wanted to make a deal. "I'll be involved in those talks, indirectly. And they'll be very important," Trump told reporters aboard Air Force One. Tensions are soaring ahead of the talks, with the US deploying a second aircraft carrier to the Middle East. The US military is preparing for the possibility of a sustained military campaign if the talks do not succeed, US officials have told Reuters. Asked about the prospects for a deal, Trump said Iran sought tough negotiations but learned the consequences of such a hardened stance last summer when the US bombed Iranian nuclear sites. Trump suggested Iranians were motivated this time to negotiate. "I don't think they want the consequences of not making a deal," Trump said.