Saudi Arabia, Egypt, the United Arab Emirates and Bahrain have added nine entities and nine individuals to their individual ban lists because of alleged links to extremist groups.
Saudi Arabia, the United Arab Emirates, Bahrain and Egypt on Tuesday announced they had blacklisted nine charity organizations and nine individuals "directly or indirectly linked to Qatari authorities," according to a statement carried by the SPA state news agency.
The four Arab states last month suspended ties with Qatar over allegations the Gulf state bankrolled extremism in the region, an accusation Doha has consistently denied.
The four states recalled their ambassadors from Doha, banned Qatar from using their airspace and ordered all Qataris to repatriate.
Among the demands of Riyadh and its allies are the closure of Qatari broadcast giant Al Jazeera, which has been banned in Saudi Arabia and the UAE.
Three organisations in Yemen and six based in Libya were accused of ties to Al Qaeda and a Syrian affiliate of the group in Tuesday's statement.
The statement also said three Qatari nationals, three Yemenis, two Libyans and a Kuwaiti citizen were involved in fundraising campaigns to support Jabhat al Nusra and other militias in Syria
Kuwait has not joined the states boycotting Qatar and is leading mediation efforts to resolve the crisis, the worst to hit the Gulf since the establishment of the Gulf Cooperation Council in 1981.
Saudi Arabia and the UAE lead an Arab military coalition allied with the Yemeni government in a violent war against Yemen's Houthi rebels. The war has killed more than 8,000 civilians since the coalition intervened in 2015, according to the World Health Organization.