The Arab Gulf countries have agreed to blacklist Hezbollah as a terrorist group, but they are still studying ways to do that, undersecretary of Bahrain’s Ministry of Foreign Affairs Hamad al-Amir told Al Arabiya on Wednesday.

Gulf Cooperation Countries, which include Saudi Arabia, Kuwait, Bahrain, Qatar and Oman were studying “correct measures” on how to officially blacklist Hezbollah, Amir said.

Bahrain blacklisted Hezbollah in April, becoming the first Arab state to do so after accusing the Lebanese group of backing and training radical Shiite groups working against Manama.

The decision by other Gulf countries came after Hezbollah openly declared its military involvement in Syria, helping the army of President Bashar al-Assad retake the town of Qusayr from rebel forces.

The Syrian conflict started with peaceful protests more than two years ago against Assad but morphed into a civil war which left at least 93,000 people killed, according to U.N. report in June.

Dhafir al-Ajmi, executive director of the Gulf Monitoring Group, said GCC should differentiate between Lebanese citizens who are sympathetic to Hezbollah and the group’s actual followers. He said the Gulf States’ action against Hezbollah may convince the group that “what it is doing is wrong and could affect a big portion of the Lebanese people.”

GCC has previously deported Lebanese citizens under suspicion that they were aiding Hezbollah.