Foreign Minister Walid al-Muallem's remarks to the United Nations General Assembly were made as Turkey and the United States press ahead with a deal to create a safe zone along Syria's border with Turkey, AP reported.
On the political front, he reaffirmed the government's support for the recently agreed committee to draft a new Constitution for the country. The foreign minister took a hard line, stressing there must be no interference from any country or timeline imposed on the process.
Muallem's speech highlighted the enormous challenges to achieve reconciliation in Syria, where over 400,000 people have been killed during the conflict and millions more have fled.
The more than eight-year conflict has also drawn numerous foreign militaries and thousands of foreign militants to Syria, many to support the now-defeated Daesh terrorist group and others still there backing the opposition and battling government forces.
"The United States and Turkey maintain an illegal military presence in northern Syria," Muallem said. "Any foreign forces operating in our territories without our authorization are occupying forces and should withdraw immediately."
If they refuse, he said, "We have the right to take any and all countermeasures authorized under international law."
There are around 1,000 US troops in Syria on a mission to combat Daesh terrorists.
Muallem described Turkey and the United States as "arrogant to the point of holding discussions and reaching agreements on the creation of a so-called 'safe zone' inside Syria" as if it was on their own soil.
Most of Syria is now under the control of the Syrian government, which is backed by Russia and Iran. However, Syrian terrorists and extremists still hold Idlib in the northwest, and US-backed Kurdish groups hold parts of the oil-rich northeast.
The Syrian government maintains that Idlib remains a hotbed for "terrorists" and Muallem vowed that its "war against terrorism" will continue "until rooting out the last remaining terrorist."
In a breakthrough on the political front, UN Secretary General Antonio Guterres announced the formation of the committee that would draft Syria's new Constitution, which he said could be an important step toward ending the war.
The UN chief announced Saturday that the committee will meet for the first time in Geneva on Oct. 30. Its rules state that a new Constitution will be followed by "free and fair elections under United Nations supervision."
The committee was authorized at a Russian-hosted Syrian peace conference in January 2018, but it took nearly 20 months for the sides to agree on the 150 members — particularly on a 50-member civil society of experts, independents, tribal leaders and women to serve alongside 50 members from the government and 50 members from the opposition. The UN was authorized to put together the civil society list but the choices faced objections, mainly from the Syrian government.
Under the newly announced terms, the "Syrian-led and Syrian-owned" committee, with UN envoy Geir Pedersen as facilitator, will amend the current 2012 Constitution or draft a new one.
Muallem stressed that the committee will operate without preconditions, its recommendations must be made independently, and "no deadlines or timetables must be imposed on the committee."