"Don't let that happen!"
Idlib is the last major bastion of the rebel groups who have been trying to oust President Bashar al-Assad since the start of Syria's civil war in 2011.
Syrian forces are massing around the northwestern province of Idlib, in preparation for the assault.
The country, which backs several opposition groups in Syria, has set up observation points around the rebel stronghold and has been seeking to stop a full-scale state offensive.
With some 3 million people now living in Idlib and the surrounding area, United Nations officials have warned that a government offensive could displace 800,000 people.
Elsewhere in his Tuesday remarks, Zarif also pointed to his last week's talks with Turkish President Recep Tayyip Erdogan and Foreign Minister Mevlut Cavusoglu in Istanbul as well as a planned summit of Iranian, Russian and Turkish presidents in Tehran and said efforts would be continued to "prevent any damage to the Syrian people and complete the process of clearing extremists".
The International Crisis Group, a Brussels-based think tank, said an all-out assault on Idlib and its catastrophic consequences could still be avoided.
Liverpool goalkeeper Alisson exchanged words with teammate after howler
For me, much more interesting is how the reaction was and it was good. "It was exciting until the end but I'm fine with that". "I am angry that I made a mistake that put the team in a hard situation", the Brazil keeper told ESPN Brasil.
"By backing an all-out offensive, Russian Federation risks undermining its long-term political objectives in Syria", ICG wrote in a nine-page briefing.
Further Iranian engagement in Syria meanwhile risks drawing Israel deeper into the conflict.
But Israeli Defense Minister Avigdor Lieberman on Monday signaled strikes could be extended to Iraq if necessary.
At the request of Damascus, Iran has been offering advisory military assistance to the Syrian army.
Britain, France and the USA, which together launched limited attacks on Syrian installations in mid-April in retaliation for an alleged Syrian chemical attack, say their red line against illegal weapon use remains in force.
But analysts still say the United States appears resigned to the likelihood of a final military victory by Syrian regime forces.
President Trump tweeted yesterday addressing to not attack Idleb because the operation could leave hundreds of people dead.
Trump has sought better relations with Russian Federation since taking office in 2017 but the United States has been unable to rein in Moscow's military and diplomatic support for Assad.