Iran says it is ready to restart nuclear enrichment on an "industrial scale" in the wake of the US decision to abandon the deal that curbs the country's nuclear ambitions.
In a statement published Friday, Iranian Foreign Minister Javad Zarif said he would embark on a round of international diplomacy to try and save the deal. At the same time, the country would make preparations to restart its nuclear program, he said.
Zarif's comments came as thousands of Iranians took to the streets in the largest demonstration since US President Donald Trump announced his decision to abandon the deal on Tuesday.
Protesters burned an American flag and railed against the US and Israel after emerging from Friday prayers in Tehran.
In his statement, Zarif said Iran would attempt to save the nuclear deal through negotiations with the European nations who were co-signatories to the deal. Zarif will meet with his counterparts from Germany, France and the UK in Brussels on Tuesday.
German Chancellor Angela Merkel said the US decision to withdraw from the deal was a serious blow. Speaking at a Catholic Day conference in Muenster on Friday, Merkel said it would be difficult to keep the deal alive, given that a "huge economic power has left".
"We hope we can, but there are a lot of things playing a role in this," she said. "We will have to discuss that with Iran."
In Tehran, anger has grown not just over Trump's move but also Israel's barrage of air attacks on Iranian targets in Syria, in response to what Israel claimed was an Iranian rocket attack on the Golan Heights.
Iran's Foreign Ministry condemned the strikes, calling them a "blatant violation of the country's sovereignty."
On Thursday Israel claimed it had struck almost all of Iran's military capabilities in Syria after the rocket attack on the Golan Heights, which Israel annexed in 1981.
There has been no official declaration by the Iranian government that it was responsible for the attack on the Golan Heights, nor any acknowledgment that Iran's military presence in Syria was impacted by the Israeli strikes.
In Iran, the news of the fighting was reported as a conflict between Syria and Israel. No mention was made of the involvement of Iran's military assets in Syria, which have long helped prop up the regime of President Bashar al-Assad.
On the streets of Tehran, anger was directed at both Trump and Israel.
Ahmad Khatami, Leader of the Friday Prayer, vowed Iran would turn "Tel Aviv and Haifa to dust" if attacked by Israel.
"We are not interested in the atomic bomb, but we are increasing our missile capabilities in other fields so that Israel cannot sleep well," he was quoted as saying by semi-official ISNA News Agency.
In a YouTube statement on Thursday, Israeli Prime Minister Benjamin Netanyahu said Iran had "crossed a red line," and that Israel's action was appropriate.
"Whoever hits us will get hit seven times over. Whoever prepares themselves to attack us will be attacked first. That is what we have done and that is what we will continue doing," Netanyahu said.
Israel annexed the Golan Heights in 1981 after capturing it from Syria in the Six Day War in 1967.
The international community has never recognized the annexation and regards the Golan Heights as Israeli-occupied territory.