TEHRAN - Iranian President Hassan Rouhani on Thursday said that regional issues should be resolved through the cooperation of regional states.

Transregional states cannot solve the problems of the region, "they have rather been the source of problems," Rouhani said at an international Islamic unity conference which kicked off in Iran's capital Tehran on Thursday.

The United States is "not the friend of Islam and the regional states", he said, adding that "they have always been source of problems, and have brought killings and bloodsheds to our region", according to official IRNA news agency.

"I have sent letters to all leaders of the region over the past weeks and have invited them to drop differences and enmity," Rouhani was quoted as saying.

Rouhani said that Iran is the friend of Saudi Arabia, Kuwait, Bahrain, the United Arab Emirates and other peoples in the region.

The 33rd International Islamic Unity Conference in Tehran will focus on the unity of the Muslims in defending Al-Aqsa Mosque.

Al-Aqsa Mosque, located in Jerusalem, is one of the holiest sites in Islam.

The three-day event will attract 350 religious scholars and political figures from 93 countries and regions.