ANKARA, Turkey (AP) — Turkish and Russian troops began joint patrols Sunday on a key highway in northwestern Syria, Turkey’s Defense Ministry said, while both the Russian government and Syrian opposition activists said the patrols were shortened because of protests.

Patrols on the highway known as the M4, which runs east-west through Idlib province, are part of a cease-fire agreement between Turkey and Russia signed earlier this month. The cease-fire ended an escalation in fighting that saw the Turkish military in rare direct conflict with Syrian government troops.

The vital highway, which runs through northern Syria from the Mediterranean to the Iraqi border, has been partially closed since 2012. Work has been underway in recent days to refurbish it for traffic. Some sections of the M4 remain under rebel control, unlike the north-south M5 highway, which Syrian forces completely recaptured in the latest offensive.

For the past three days, residents along rebel-held parts of the M4 have protested in rejection of Russian troops patrolling the road because of Moscow's strong support to Syrian government forces.

“The first Turkish-Russian united land patrol was carried out on the M4 highway in Idlib with the involvement of land and air elements,” Turkey's Defense Ministry said in a statement.

Russia's Defense Ministry said Turkey and Russia carried out their first joint patrol mission along the M4 highway Sunday adding that “the patrols' route was shortened” after militants used women and children to block the way. The Defense Ministry's statement was carried by state-run news agency Tass.

Ankara has been given additional time to ensure the safety of troops taking part in joint patrols, the Russian Defense Ministry said.

Syrian opposition activists said residents blocked the highway with burning tires near the village of Nairab on the southern edge of Idlib in rejection to patrols by “Russian occupation forces."

The Britain-based Syrian Observatory for Human Rights, an opposition war monitor with activists on the ground in Syria, said the joint patrols were not successful as they moved a short distance west of the government held town of Saraqeb before being stopped by the protests.

It added that jihadi groups have threatened to attack Russian forces on the highway. Idlib is mostly controlled by al-Qaida-linked militants.

Ankara backs some of the opposition groups in Idlib, the fighters' final stronghold against the Russian-backed forces of Syrian President Bashar Assad.

The Idlib offices of the humanitarian Syrian Arab Red Crescent group were ransacked Saturday by the al-Qaida-linked Hayat Tahrir al-Sham, or HTS, the strongest faction in the rebel-held province.

On Sunday, the United Nations and the International Committee of the Red Cross condemned the offices' takeover, saying items were stolen or destroyed while Red Crescent members were detained and harassed.

Activists in Idlib quoted a statement of the so-called Salvation Government, an arm of HTS, as saying the move against the Red Crescent was because of corruption among its members.

There's a growing humanitarian crisis in Idlib province, where hundreds of civilians have been killed and 1 million have been sent fleeing towards the Turkish border because of the Syrian government's ground and air offensive, which began in early December.

Some 60 Turkish soldiers have been killed in Idlib since the start of February. Russian officials visited Ankara last week to hammer out the cease-fire. After four days of talks, Turkish Defense Minister Hulusi Akar said Turkey hoped the deal would prove to be permanent.

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.

___

Associated Press writers Albert Aji in Damascus, Syria and Bassem Mroue in Beirut contributed to this report.