Iran's foreign minister has criticized demands for the resignation of Syrian President Bashar Assad, saying such calls will prolong the Arab country's civil war.

Mohammad Javad Zarif says those demanding Assad's ouster "are responsible for the bloodshed in Syria."

Zarif didn't name any specific country but was likely referring to Turkey's and Saudi Arabia's repeated calls for Assad to step down. The two Sunni Muslim countries have supported rebels fighting against Assad.

The Shiite-majority Iran is a leading patron of Assad and Tehran has also sent military advisers to Damascus to help the Syrian president's troops against the Islamic State group.

Zarif spoke at a press conference on Monday with his visiting Spanish counterpart, José Manuel García-Margallo. The top Iranian diplomat also said the Syrian crisis has no military solution.