TEHRAN - Iran is ready to hold direct talks with European parties to a 2015 nuclear pact, Iranian Press TV quoted an unnamed source as saying on Wednesday as Tehran's top nuclear negotiator visited Brussels to discuss a resumption of stalled nuclear talks.

"Iran has formally voiced preparedness for direct talks with the three European parties to the nuclear deal," the source told Press TV. "Iran invited the three states for visits to Tehran or offered trips to the trio’s respective capitals for such talks, but it has received no response so far."

In April, Iran and six world powers started negotiations to revive the agreement which former US President Donald Trump quit in 2018 and reimposed sanctions that have crippled Iran's economy.

The talks have been on hold since June, two days after hardline cleric Ebrahim Raisi was elected Iran's president.

Concerned about Iran's nuclear advances, Western powers have urged Tehran to return to negotiations in Vienna. Tehran says it backs result-oriented negotiations, but has not announced when it will return to the talks.

Since 2019, Iran has gradually breached limits imposed by the nuclear deal but says its nuclear steps are reversible if US President Joe Biden lifts all his country's sanctions on Iran.

Iran's top nuclear negotiator, Ali Bagheri Kani, is in Brussels for a second meeting this month with Enrique Mora, a European Union official who coordinates nuclear talks between Tehran and six powers.