Buses carrying hundreds of Islamic State militants and their families from the border area between Lebanon and Syria have arrived in eastern Syria as part of a deal to end the extremist group's presence there, reports said.
About 600 militants were allowed to leave as part of a deal, negotiated by Lebanon's Hezbollah, in exchange for identifying the location of the remains of Lebanese soldiers captured by IS in 2014 and later killed.
The deal has provoked controversy in Lebanon, as some have voiced opposition to negotiations with the militants.
It has also angered Iraqis who expressed resentment at the deal that effectively puts the militants on their border. Baghdad accused Hezbollah and the Syrian government of preferring to strengthen IS near the Iraqi border, rather than eliminating the militant group.
"Any deals or understandings between the warring parties inside Syria or in the region must take into consideration the security of Iraq and not to lead to anything that poses any threat to our national security," Iraqi government spokesman Saad al-Hadithi said.
Mr al-Hadithi said the Iraqi government "will firmly face any threat to Iraqi territories".
Some Iraqis also expressed resentment on social media.
"Who's going to pay for the delivery sent by Hassan Nasrallah to us?" wrote well-known writer Saleh al-Hamdani on his Facebook page, referring to Hezbollah's leader.
"Will Hashed (Shiite militias) or Federal Police or Counter Terrorism Forces pay for it?"
Baghdad-based analyst Hisham al-Hashimi wrote that Iraq's "selfish ally preferred to throw Daesh (IS) danger from Lebanon to Iraq, while Iraqis demolished the second-largest city (Mosul) in order not to enable Daesh militants to flee (to Syria) and damage the neighbour".
The Lebanese government and Hezbollah have defended the deal that allowed IS safe passage to the eastern province of Deir el-Zour, an IS stronghold, saying it was the only way Lebanon could uncover the fate of its kidnapped soldiers and recover their remains.
IS's departure leaves the border between Syria and Lebanon free of Sunni militant extremists for the first time in years.
Syrian state-run news agency Sana said the buses carrying the militants arrived on Tuesday to a handover point in the town of Hamimiyah in eastern Deir el-Zour. They are expected to continue to the town of Boukamal, near the Iraqi border.