Turkish troops fired tear gas and live bullets at protesters blocking a major highway in northwest Syria early Sunday, killing two people and wounding others, opposition activists said.
The protesters have been blocking part of the highway near the government-held village of Nairab in Idlib province for weeks to prevent joint Turkish-Russian patrols.
Patrols on the M4 highway, which runs east-west through Idlib province, are part of a cease-fire agreement between Turkey and Russia signed in early March. The cease-fire ended an escalation in fighting that saw the Turkish military in rare direct conflict with Syrian government troops.
Turkish and Russian troops officially began joint patrols on March 15 on the M4. But the patrols had to be shortened because of protests by those opposed to the deal, which allows Russian troops to patrol rebel-held areas.
Turkey backs the opposition in Idlib, while Russia has been a main backer of Syrian President Bashar Assad's government. Moscow joined the war in 2015, helping turn the balance of power in Assad's favor.
The Britain-based Syrian Observatory for Human Rights, an opposition war monitor, said Turkish troops removed debris from the highway Sunday morning and were met by protesters who threw stones at the force, which later opened fire. The Observatory said the two people killed were militant fighters.
The activist collective Al-Dorar Al-Shamia described the two killed as protesters, and said three others were wounded in Sunday's shooting.
There was no immediate comment from the Turkish military.
Turkey has been working on opening the highway by ending the sit-in by supporters of militant groups in rebel-held parts of Idlib, led by the al-Qaida-linked Levant Liberation Committee.
The vital highway, which runs through northern Syria from the Mediterranean to the Iraqi border, has been partially closed since 2012. Some sections of the M4 remain under rebel control, unlike the north-south M5 highway, which Syrian forces completely recaptured in the latest offensive.
Turkey and Russia already conduct joint military patrols elsewhere in Syria. Following an agreement that halted Turkey's attack on Kurdish forces in October, soldiers from the two countries monitor an area of northeast Syria along the Turkish border.