With the help of Russian Federation and Iranian-backed Shia jihadist militias, the Syrian regime of President Bashar Al-Assad has gained the military upper hand in the six-year conflict. Iran, Assad's other major ally, also backed it.
The Riyadh-based HNC, which includes political and armed groups, cautioned against attempts to "partition the country through vague meanings of what has been called ..."
The aircraft safety memorandum was signed in October 2015 after Russian Federation began bombing targets in Syria to support Syrian government forces in their fight against Islamic State and other armed groups. That arrangement was suspended last month after the U.S. Tomahawk missile barrage on a Syrian air base, fired in response to a deadly chemical gas attack in Syria that was blamed on Assad's government. However, in some areas there have been local, unsubstantial clashes.
Russian Federation and Iran's military support has been crucial to the survival of Assad's government and the victories of his military.
But US participation has been lacking and Syrian rebel groups are not stakeholders.
The conflict occurred in the rebel-held village of al-Zalakiyat as fighter jets fired in the Hama countryside, reported the Syrian Observatory for Human Rights.
Separately, a Syrian monitoring group and an official with a US -backed force said on Thursday that Kurdish-led fighters have captured all parts of a Tabqa, a northern town in Syria that was held by ISIS.
The Syrian opposition coalition has denounced the deal as an attempt to "divide Syria" and hand government troops military victories they would otherwise be unable to achieve.
"The bombardment has not stopped, it is no different from before", he told Reuters. While the plan was raised several times before and after his inauguration in January, details on how and where such safe zones would be established were scant.
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The operations will be directed only against the militants who have done this particular cowardly act, he said. His wife said: "We want strict action, instead of strong condemnation of the brutal killing".
The agreement also included creating conditions for humanitarian access, medical assistance and the return of displaced civilians to their homes.
The Astana talks were meant to shore up an oft-violated ceasefire which was originally agreed in December. It is unclear though who will be responsible for policing the air space and what the consequences would be for breaking the interdiction.
Lavrentyev added that planes from the US -led coalition would still be allowed to operate against Islamic State targets in specific areas, but would be banned from entering "de-escalation zones", as would planes from all other air forces, including those of Russian Federation and Syria.
The agreement, the latest endeavor to reduce violence in the conflict-ridden Arab country, calls for delineating zones where frontlines between the Syrian government forces and militants would be frozen and fighting halted.
The deal was negotiated at Russian-brokered talks in Astana which have taken place outside of United Nations-sponsored peace talks in Geneva.
The U.S. was represented at the talks in Kazakhstan though Nauert said it was neither a "direct participant" nor a party to the agreement.
The US appeared uneasy with the deal, with the state department saying Washington welcomed efforts to reduce violence in Syria but did not trust Iran's role in the agreement.
The largest covers northern Idlib province, the opposition-held enclave near the Turkish border, and parts of neighboring Aleppo, Hama and Latakia provinces where fighting has been fierce.