The United States on Friday announced a fresh round of sanctions targeting 15 entities, two individuals, and 14 shadow fleet vessels to curb Iran’s oil exports.

The move targets what Washington describes as a network of shippers and traders involved in trading and acquisition of Iranian crude oil, petroleum products and petrochemical products, which constitutes Iran’s primary source of income.  

The sanctions announcement came as Iran and the United States held indirect talks on Friday, an effort that appeared to reset discussions over Tehran’s nuclear programme amid heightened regional tensions.

Iranian foreign ministry spokesperson Esmaeil Baqaei said that nuclear talks with the U.S. concluded and that there was a “consensus” that the negotiations would continue.

Baqaei stressed the negotiators would now return to their capitals for consultations before making decisions about the next round of negotiations.

Senior US and Iranian officials are set to continue discussions after talks on Friday, the Iranian foreign ministry noted, amid a crisis that had raised fears of a conflict between the countries.

It remains unclear just what terms Iran is willing to negotiate at the talks. The United States did not publicly comment on the outcome of the talks.

The sanctions are the latest step in a mounting pressure campaign under the administration of US President Donald Trump.

The US has a long history of sanctions against Iran and its oil sector. But the latest slate of sanctions on Friday comes as the two countries hold talks to try to lessen the escalating tensions between them.

In accordance with the U.S. State Department announcement, the sanctioned vessels have collectively transported “millions of barrels of Iranian crude oil” while “regularly engaged in dark activity and other deceptive shipping practices, endangering other vessels and legitimate trade flows.”   

This action also includes sanctions against four entities that have allegedly engaged in the transshipment, sale, and purchase of Iranian-origin petrochemical products, as well as the manager of one of the companies.

The penalties aim to block them from using the U.S. financial system and prohibit American citizens from making any kind of transactions with the designated entities or persons.