Iran has urged its citizens not to travel to Iraq, after deadly bombings, targeting Shi'ite pilgrims, Tuesday rocked Karbala and Baghdad.

Iran's Interior Ministry said pilgrims should not cross the border into Iran.

Iranian state television reported more than two dozen Iranians were among those killed Tuesday, when a series of explosions shook the Iraqi cities of Karbala and Baghdad.

Fifteen suspects have been arrested in connection with the attacks, including several who speak Farsi, and are believed to be Iranian nationals.

Iran's Foreign Ministry issued a statement Wednesday, saying that terrorists use all kinds of methods to mask their true identities, and speaking different languages could be part of their cover. The statement also said many of those killed were innocent Iranians, which proves that Iran is on the front-line of fighting terrorism.

Iran has condemned the bombings, and blamed the coalition forces for failing to provide adequate security for the worshipers.

Hundreds of thousands of Shi'ite Muslims traveled to Karbala for the festival, which had been banned under Saddam Hussein's regime.