Turkish Foreign Minister Mevlu Cavusoglu had said earlier that Erdogan and Putin would hold talks on the crisis in Syria on Monday.
President Recep Tayyip Erdoğan will meet his Russian counterpart Vladimir Putin in Sochi on Monday to discuss the situation in Syria's Idlib amid increasing Russian and Assad regime attacks on the last opposition enclave.
Stephane Dujarric told reporters at the U.N.'s NY headquarters the majority of those displaced between September 1 - 9 have fled to northern Idlib near the Turkish border amid an escalating air and ground offensive by regime and Russian forces there.
The presidents of Turkey, Iran and Russian Federation met in Tehran on Friday but failed to agree on a ceasefire in Idlib.
Russian Federation and Iran are key allies of Syrian President Bashar al-Assad's regime.
The UN, which has warned a full-fledged assault on Idlib could create the century's "worst humanitarian catastrophe", has created a plan to help up to 900,000 people who could flee the onslaught.
The US has struck Syria twice after claims of chemical weapons use by the government in Damascus, Haley said on Wednesday in a Fox News interview.
The battle could bring an end to a seven-year-old uprising-turned-civil war, but at the cost of a humanitarian disaster on a scale yet unseen in the bloody conflict.
"We are making an effort for a ceasefire in Idlib", he said, repeating Turkey's call for targeted operations against jihadist militants, including the Tahrir al-Sham alliance, instead of an indiscriminate onslaught.
Idlib and surrounding areas are home to almost 3 million people, half of them already displaced by violence in different parts of Syria.
Turkey fears that a large-scale offensive against Idlib will cause a new influx of refugees into its territory, where more than 3 million Syrians have already taken refuge.
The inquiry said in a 24-page report that over 1 million Syrian men, women and children have been displaced so far this year "with most now living in dire conditions". "We hope it will not be needed".
Earlier, Maas criticized the United States position on Nord Stream-2, saying that Washington's attempts to influence the European energy policy through sanctions are unacceptable.
The Russian foreign minister also raised the possibility of rebels using chemical weapons against government troops in Idlib as grounds for an offensive but added: "What is being presented at the moment as the beginning of a Russian-backed offensive by Syrian forces is not a faithful representation of the facts".
"In conducting airstrikes beginning on 20 January, the Turkish air force may have failed to take all feasible precautions prior to launching certain attacks, in violation of global humanitarian law", the report said.