We will stand by the dear people of Lebanon under all circumstances, says Ali Larijani, who was recently appointed as the head of Iran's highest security council, when he landed in Beirut.
There he was welcomed by dozens of Hizbollah supporters.
Larijani is expected to meet Lebanon's president Joseph Aoun, prime minister Nawaf Salam and the parliament's speaker, Hizbollah-associated Nabih Berri.
The trip is being made at a tense time for the relations between Iran and Lebanon, since the Lebanese government recently made a decision to disarm the powerful militia group, which has very close ties to Iran.
Hizbollah has responded that the government's decision will be treated "as if it did not exist". Iran has also expressed strong opposition to the disarmament plans.
