Iranian President Hassan Rohani has joined Russia, Syria, and Turkey in opposing a new 30,000-strong border guard force inside Syria that the United States says is needed to keep Islamic State extremists out of the country.
"The new plan that the Americans have in mind for Syria is a violation of international laws and a plot against the sovereignty and security of Syria and the region," Rohani was quoted by Iranian state media as saying on January 16 during a meeting with the visiting Syrian parliament speaker in Tehran.
The U.S.-led coalition battling IS in Syria said on January 14 that the new border guards would be comprised of fighters from the Kurdish-led Syrian Democratic Forces and would operate along the borders with Turkey and Iraq to keep IS militants who last year were routed from most parts of Syria from returning to the country.
The plan met with strong opposition from Turkey, Russia, and Syria on January 15, with Turkish President Recep Tayyip Erdogan saying he was preparing a military operation to eliminate the Kurdish-led border force.
Erdogan views Syria's YPG Kurdish militia as a terrorist organization aligned with armed Kurdish separatists who have been fighting the government in Turkey for decades.
Syrian President Bashar al-Assad also vowed to crush the new border force and drive U.S. troops from Syria, while Russia charged that the plan showed the United States intends to partition Syria by allowing Kurdish forces to consolidate their hold on the approximately 25 percent of Syrian territory they now control after liberating it from IS.
Iran has been Syria's closest ally in the country's nearly seven-year civil war against Sunni rebel forces.
Iranian Foreign Ministry spokesman Bahram Qasemi also said on January 16 that the planned U.S.-backed border force would "fan the flames of war" and raise tensions.
"The U.S. announcement of a new border force in Syria is an obvious interference in the internal affairs of this country," Qasemi was quoted as saying by state news agency IRNA.
Qasemi urged all U.S. forces to leave Syria immediately.
The United States heads an international coalition that provided air support and special forces troops to aid the SDF in pushing IS out of its strongholds in northern and eastern Syria last year, including its self-proclaimed capital of Raqqa.
While IS has been mostly ousted from the region, U.S. Defense Secretary Jim Mattis has said he will keep U.S. troops in Syria to provide protection for allied SDF fighters and help them keep IS from returning to the region while they establish a civilian-led democratic government there.
Meanwhile, U.S. Secretary of State Rex Tillerson is due to deliver a speech on what the United States believes is "the way forward in Syria" on January 17 in Stanford, California, the U.S. State Department announced on January 16.