MASHHAD, Nov. 8 (MNA) – Hundreds of thousands of pilgrims from Iran, Afghanistan, Pakistan, Iraq, Azerbaijan and several other countries have flocked to the holy city of Mashhad in the northeastern province of Khorasan Razavi to mark the martyrdom anniversary of the eighth Shia Imam, Imam Ali ibn Musa al-Reza (PBUH) at his mausoleum.