Iran will help oppressed people in the region as much as it can, Supreme Leader Ayatollah Ali Khamenei warned.
"Yemen, Bahrain and Palestine are oppressed, and we protect oppressed people as much as we can," state news agency IRNA quoted Khamenei as saying in an address to Iranian leaders and diplomats from the Islamic world.
His comments are likely to be taken by Gulf Arab leaders, who on Thursday met with US President Barack Obama to address security issues, as evidence that Iran is trying to aggressively expand its influence in the region.
An increasingly tense standoff between Iran and Saudi Arabia has added a sectarian dimension to regional conflicts, particularly in Yemen where a Saudi-led coalition of Sunni Arab states is carrying out air strikes against Shi'ite Houthi rebels allied to Iran.
The standoff has also raised concerns for shipping in the Gulf, a major oil transport route. In the past month, Iranian forces have twice tried to seize commercial ships to settle legal disputes.
"Security in the Persian Gulf is in the interests of everyone... If it is insecure, it will be insecure for all," Khamanei said according to IRNA.