Al-Assad said: "Iran and Syria support the peoples of the region and the enemies will only reach their goals by creating pessimism and disunity amongst Muslims."
"Creating conflict between Shia and Sunni in Iraq and Lebanon is the final card that America and its allies have"
Bashar al-Assad, Syrian president
Ahmadinejad agreed that the region "should be careful about the enemies' efforts to create division and conflict amongst Muslims and make sure they do not reach their sinister goals.
"Under the current conditions it is necessary that Islamic countries preserve their vigilance, unity and wisdom to prevent the establishment of new conspiracies."
Al-Assad met former president Akbar Hashemi Rafsanjani and is also scheduled to meet Iran's supreme leader Ayatollah Ali Khamenei.
The Syrian president told Rafsanjani: "Creating conflict between Shia and Sunni in Iraq and Lebanon is the final card that America and its allies have... they try to cover their failure with false propaganda."
Al-Assad was the first world leader to visit Ahmadinejad following his election victory, five days after he took office, and relations have remained strong ever since.
The Iranian president visited Damascus in January 2006, where he held talks with al-Assad and Syria-based political leaders of Palestinian groups.
Washington is planning to send more troops to bolster the US-led force of about 140,000 soldiers in Iraq, and accuses the two countries of helping stir up insecurity there.
Damascus has also been accused of escalating violence which has dogged Lebanon since the assassination of Rafiq al-Hariri, the former prime minister, in 2005.
Tehran has been accused of arming the Shia group, Hezbollah.
"I believe there is a widely available diplomatic solution that the people of both America and Iran want"
thesavior, Edmonton, Canada
Syria is a staunch supporter of Iran's controversial nuclear programme, which the US alleges is a cover for making nuclear weapons.
Israel, an ally of the US, is believed to be the only nuclear-armed state in the Middle East although it has never officially confirmed this status.
Iran insists its atomic drive is solely aimed at generating energy, to which it has every right within international law.