Ambassadors of Lebanon, Jordan, Iraq, Qatar, Kuwait and Saudi Arabia have been invited to the ministry, where Turkish ambassador Sedat Onal will brief them about the operation, the sources, who asked not to be named due to restrictions on talking to media, said.
The Foreign Ministry also invited European Union's Turkey Delegation head Christian Berger to the ministry headquarters to brief the envoy about the operation.
Foreign Minister Mevlut Cavusoglu on Saturday said Turkish authorities have informed the Syrian regime about the ‘Operation Olive Branch’.
"We have informed [the regime in Syria] through a written note," Cavusolgu told Turkish NTV broadcaster in a live interview.
"This does not mean that we have taken permission from them. We have sent such a note because we are acting in accordance with the international law," he added.
On Saturday, envoys and mission chiefs of permanent members of United Nations' Security Council -- United States, Russia, United Kingdom, France, China as well as Iran -- were also invited to the ministry for a similar briefing.
Turkey launched the military operation in Afrin on Saturday at 5 p.m. (1400GMT).
The operation aims to establish security and stability along Turkish borders and the region as well as to eliminate terrorist groups PKK/KCK/PYD-YPG and Daesh and to protect Syrian people from the oppression and cruelty of terrorists.
The operation is being carried out under the framework of Turkey’s rights based on international law, UN Security Council’s decisions and self-defense right under the UN charter, according to the military.
The PYD/PKK is the Syrian offshoot of the PKK terrorist group, which has been designated a terrorist organization by Turkey, the U.S. and the EU.