Washington DC, April 10 -- US Vice President JD Vance on Friday departed for Pakistan's capital of Islamabad to take part in talks with Iran, expressing optimism about the negotiations while warning against any lack of sincerity from Tehran.

Addressing reporters before departure, Vance said the United States is open to constructive engagement if Iran approaches the discussions in good faith.

"We're looking forward to the negotiation. I think it's going to be positive. As the president of the United States said, if the Iranians are willing to negotiate in good faith, we're certainly willing to extend the open hand," he said.

However, he cautioned that Washington would not respond favourably if Iran attempts to act in bad faith during th...