A car loaded with explosives blew up near a bus carrying members of Iran's elite Revolutionary Guards in southeastern Iran, killing 18 of them, the state-run news agency reported today.
The car stopped in front of the bus near Zahedan, the capital of Sistan-Baluchestan Province, the official Islamic Republic News Agency reported. It called the attack a terrorist operation and said the car's occupants fled on motorbikes seconds before the car exploded.
"This blind terrorist operation led to the martyrdom of 18 citizens of Zahedan," IRNA quoted a Guards commander, Qasem Rezaei, as saying.
State-run television said the bus had been taking them to work when the attack took place.
There was no immediate claim of responsibility but Rezaei blamed "insurgents and elements of insecurity" for the attack.
Hossein Ali Shahriyari, a deputy representing Zahedan, told an open session of the parliament today that "insurgents and drug traffickers" were behind the attack.
Shahriyari called lawless regions in southwestern Pakistan a safe haven for Iranian insurgents and drug traffickers, and called on the government to take up the issue with Islamabad.
"Why doesn't our foreign diplomatic apparatus deal with Pakistan, whose soil has turned into a safe heaven for insurgents," he asked. His speech was broadcast live on state-run radio.
Soltan Ali Mir, a local Interior Ministry official, said five of those behind the explosion were arrested, IRNA reported. It did not say how many were involved.
"Two of the terrorists were arrested (immediately) after the attack. Police confiscated a camera and hand grenades from them. Later, three other terrorists behind today's bomb explosion were arrested," IRNA quoted Mir as saying.
The passenger car stopped in the middle of the road at around 6.30am in Ahmadabad district on the outskirts of Zahedan, IRNA said. After the bus stopped, the car's occupants fled and the vehicle exploded.
Zahedan and its surroundings, which lie near Iran's borders with Pakistan and Afghanistan, have been the scene of clashes between police and drug smugglers in the past.
Three small explosions injured two people in Zahedan last June, but today's explosion was the deadliest in years.
The explosion comes at a time of high tension between Iran and the United States over insurgents in Iraq and Iran's controversial nuclear programme.