Attempts by the United States to break up the strong ties between Damascus and Tehran "are dreams and illusions," Larijani told reporters in the Syrian capital ahead of a visit to the region by US President George W. Bush.
On Wednesday, Bush begins an eight-day tour of Israel, the West Bank town of Ramallah and five Arab states in a bid to hasten Israeli-Palestinian peace talks and increase pressure on Iran over its nuclear programme.
Earlier in Tehran, the Iranian foreign ministry spokesman, Mohammad Ali Hosseini, slammed the visit saying it was aimed at interfering in relations between regional states.
Larijani made his remarks after talks in Damascus with Syrian President Bashar al-Assad and Vice President Faruq al-Shara.
Assad and Larijani discussed "the constructive cooperation which is constantly growing" between their two countries, as well as "the need to guarantee security and stability" in the region, the official SANA news agency
"Syria and Iran are bound by solid ties of friendship and must consult one another permanently on sensitive regional issues," Larijani told reporters, adding that the two allies have similar views on Iraq and Lebanon.
Larijani also expressed hope that Arab League chief Amr Mussa will be able to convince feuding Lebanese politicians to adopt an Arab League plan calling for the election of army chief General Michel Sleiman to the presidency.
Lebanon has been without a president since pro-Syrian Emile Lahoud completed his term of office on November 23 amid sharp divisions between the Western-backed government and the opposition, which is backed by Syria and Iran.