Iran's Foreign Minister Mohammad Javad Zarif says Tehran is ready for more prisoner exchanges with the United States, days after the two countries exchanged two of their detained nationals.

'After getting our hostage back this week, fully ready for comprehensive prisoner exchange,' Zarif tweeted on December 9, adding: 'The ball is in the [U.S.'s] court."

The December 7 prisoner exchange between the United States and Iran involved Xiyue Wang, a Princeton graduate student detained by Iran on widely dismissed espionage charges, and Masud Soleimani, an Iranian scientist held by the United States for violating U.S. sanctions against Iran.

Also on December 9, Iranian government spokesman Ali Rabiei said Tehran had always sought an 'all-for-all release' with the United States, according to the official government news agency IRNA.

Rabiei said efforts to swap prisoners were not linked to any other U.S.-Iranian talks, which he said would only be possible if Washington lifted sanctions against Iran and returned to the 2015 nuclear deal between Tehran and world powers.

Tensions have heightened between Iran and the United States since U.S. President Donald Trump last year pulled Washington out of the agreement and started reimposing tough sanctions that have crippled the Iranian economy.

Washington has called on Iran to release all the Americans it is holding.

In October, Iran said it has given the U.S. a list of some 20 Iranians held in U.S. prisons on charges of circumventing U.S. economic sanctions.

With reporting by Reuters, AP, and IRNA

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