The U.N. warned last week that such an offensive would lead to the "worst humanitarian catastrophe in the 21st century".
Syrian government and Russian warplanes began air strikes in Idlib last week in a possible prelude to a full-scale offensive and aid organizations said several medical facilities have already been targeted.
"This (A full-scale attack) would unleash a humanitarian nightmare unlike any seen in the blood-soaked Syrian conflict", said the UN chief in a press encounter at UN Headquarters in NY.
Russian Federation will brief the United Nations Security Council on Tuesday about the results of the Tehran summit it held with Iran and Turkey on the fate of Syria's Idlib province, diplomats said.
"Fighting terrorism does not absolve warring parties of their core obligations under global law", said Guterres, who directly appealed to Iran, Russia and Turkey to spare no effort to protect civilians, "preserve basic services such as hospitals, ensure full respect for worldwide humanitarian law".
Sinirlioğlu warned "an all-out military operation would result in a major humanitarian catastrophe". Erdogan urged the worldwide community to take action or face "security risks for Turkey, the rest of Europe and beyond".
Guterres said he understands that "the present situation in Idlib is not sustainable and the presence of terrorist groups can not be tolerated".
Anniversary of deadly 9/11 attacks gives ‘perspective’ as NAFTA talks resume: Freeland
The governing Liberal Party is holding its caucus retreat in Saskatoon on Wednesday and Thursday and it's not known whether Ms. Still, "with a bit of flexibility, things could move quickly", the source added.
There is an urgent need to make greater progress in the Geneva process, and in particular the creation of a constitutional committee as part of the overall political package, he said. Whatever the United States promises them, Kurds must look back and understand how they were betrayed by the U.S. in the last hundred years. "The consequences of inaction are huge", Erdogan said.
According to Russian Foreign Minister Sergey Lavrov, there is "no doubt" that Islamic militants with ties to Western intelligence agencies that are hostile to Assad's regime are planning a false-flag chemical weapons attack in Idlib province, the scene of fierce fighting between forces loyal to the Syrian regime and terrorist groups opposed to it.
The powerful allegations come at a time when President Donald Trump and officials in his administration continue to warn Assad of potential consequences for using chemical weapons or otherwise attacking forces openly at war with his regime.
Secretary of Defense James Mattis declined to say Tuesday whether the USA would take military action against the Syrian regime should it use chemical weapons, but he did say Syrian leader Bashar al-Assad has "been warned".
Rebel-held Idlib province and adjacent rural areas, worn down by a succession of government victories in recent months.
Regime leader Bashar al Assad has now set his sights on Idlib, and his forces have stepped up bombardment of the densely populated province since the beginning of the month.
"Since September 4, an uptick in violence has killed scores of civilians and displaced more than 30,000 people, Laerke said". The UN has described it as a "dumping ground" for people evacuated and displaced from elsewhere in Syria during the seven-year war.