Annan, who is on a 10-day visit to the Middle East, will stay in Iran for two days.

He is expected to meet Iranian President Mahmoud Ahmadinejad, Chairman of the Expediency Council Akbar Hashemi Rafsanjani, Secretary of Supreme National Security Council (SNSC) Ali Larijaniand Foreign Minister Manouchehr Mottaki.

The two sides are scheduled to discuss the implementation of UN Security Council Resolution 1701, which suspended a 34-day-long battle between Israel and Lebanese Hezbollah that killed more than 1,200 people in Lebanon, overwhelmingly civilians, and 160 Israelis, mostly soldiers.

Iran's nuclear issue will also be the focus during their meetings.

Annan's visit came just two days after Iran failed to meet a UN resolution deadline that demands the country to halt enrichment work before Aug. 31.

On Thursday, International Atomic Energy Agency chief Mohammed ElBaradei presented a report to the UN Security Council, saying "Iran has continued enriching uranium despite a UN nuclear deadline for it to suspend or face possible sanctions."

However, Iran has repeatedly said that it would not give in "one iota" on its nuclear right and would never bend to international pressure on the controversial nuclear issue.