What are the main points of contention between US and Iran?

Uncertainty over a second round of US-Iran talks in Islamabad has persisted over the past few days as the fragile truce between the two countries nears its end. While a US delegation — headed by US Vice President JD Vance — is expected in Islamabad for negotiations, the Iranian side has not yet confirmed its participation in the high-stakes talks. US President Donald Trump, on the other hand, has ramped up his threats against Iran, stating that it could “face problems” if it did not return to th...