From a Turkish perspective, Ankara is fighting terrorism.
Turkey has a large Kurdish population, mostly living in the south-east of the country, and the Kurdistan Workers' Party (PKK) has been waging a guerrilla war there for decades, leading to a tough military reaction from the Turkish state.
Ankara says that the Kurdish People’s Protections Units (YPG), who are fighting Bashar al-Assad's regime in northern Syria, are part of the same movement as the PKK.
“The YPG and the PKK, organisationally they are separate organisations,” says Joost Jongerden, a Kurdistan specialist at the University of Wageningen
“But, at the same time, both organisations have a similar ideological orientation, a strong orientation to the fold of Abdullah Ocalan."
Ocalan is the jailed PKK leader who was himself based in Syria until 1998, after which he moved through Russia, Greece and Italy before being eventually captured in Kenya.
“But Turkey also says that the YPG is a threat to Turkey’s internal security and that’s not the case," says Jongerden. "We did not see any incident initiated by the YPG against Turkey or Turkey’s internal security."
Russia pulls out
Turkey seems to have waited until Russia started withdrawing its troops from the region before launching the attack.
“They want to establish essentially a 30-kilometre cordon sanitaire to prevent the PKK–YPG forces from firing shells into Turkey and for sending agents,” says Iltar Turan, a political scientist with Bilgi University in Istanbul.
“It also involves the restoration of public order which will allow people who were driven away from the Afrin region because of the YPG, to come back."
The YPG drove non-Kurds out and brought in people of Kurdish origin to transform the ethnic composition of the area, he claims.
Muted protest from US
The YPG were fighting the Islamic State armed group, backed and supported by the US and functioning as Washington’s boots on the ground.
But Washington has not done much to defend its ally in the region. US Defense Secretary Jim Mattis said that Turkey gave advance warning of the attack and the Trump administration has limited its protests to describing the Turkish operation as “destabilising”.
The delicate issue is that both Turkey and the US are members of the Nato military alliance.
Turkey has called upon other Nato members to support Ankara in this operation.
Only France has spoken out strongly against Turkey’s offensive.
Turkish Kurds protest
Meanwhile, Kurds living inside Turkey have criticised Ankara’s military operation against their brothers in Syria.
“Kurds inside Turkey have reacted by protesting the decision to start operations against Afrin,” says Jongerden.
“But it is very difficult to express discontent at the headquarters of the Kurdish party at Diyarbakir in the south-east of Turkey."
According to Jongerden, Turkish police closed the local offices of the opposition pro-Kurdish People's Democratic Party (HDP).
“They wanted to make a statement in front of the party office but at the moment they wanted to do that, police made it impossible for party members to make their statement," he says.
Turkish president Recip Tayyip Erdogan set the tone on Sunday by saying that anyone who opposes the Afrin operation will be considered to be “supporting terrorism”.
“So they do not have many possibilities to express their discontent,” Jongerden comments.