The head of Iran's parliament's foreign affairs committee accused the United States of seeking to destabilise Syria after talks on Tuesday in Cairo with Arab League chief Nabil al-Arabi.
Alaeddin Borujerdi's visit to Cairo was the first since former president Hosni Mubarak resigned in February after 18 days of massive streets protests.
Borujerdi told reporters he discussed with Arabi "changes" sweeping some Arab countries, including the unrest in Syria where rights groups say a government crackdown on pro-democracy protesters has killed more than 2,000 people. "We must help Syria so we do not allow the United States to interfere in regional affairs," Borujerdi told reporters, accusing Washington of trying to destabilise Iran's ally Syria.
His call comes a day after Kuwait and Bahrain withdrew their ambassadors from Damascus, following in the steps of Arab heavyweight Saudi Arabia, in moves welcomed by the United States.
Washington has said it is "encouraged and heartened" by a tougher Arab stand on Syria.
The recalls have increased the regional isolation of President Bashar al-Assad of Syria, which has also come under mounting criticism for its deadly crackdown on protesters including from the Arab League.
Arabi on Sunday urged the Syrian authorities "to bring an end immediately to acts of violence and campaigns by the security forces against civilians."
Borujerdi meanwhile called for closer ties between Egypt and Iran.
Egypt cut diplomatic ties with Shiite Iran after its 1979 Islamic revolution, and Mubarak's government constantly accused Iran of meddling in Egypt and region.
Arabi had previously said, during his stint as foreign minister after Mubarak's ouster, that Egypt wanted to improve ties with Iran but warned Tehran of interfering in Arab affairs.