Iran and Syria say they will form a united front to confront challenges and threats from other countries.

Syrian Prime Minister Naji Otri, who is in Tehran Wednesday, said the meeting of the two allies comes at a very important and delicate time, when both countries are facing numerous challenges.

Iran's vice president, Mohammad Reza Aref, told reporters that Tehran is ready to help Syria on all grounds to confront threats.

Iran has been under intense U.S. and European pressure to abandon its nuclear activities, while Washington has accused Syria of being a haven for anti-Iraqi insurgents.

Tuesday, Washington recalled its ambassador to Syria for consultations, a day after Lebanon's former prime minister, Rafik Hariri, was killed in a Beirut car bombing.