UPDATE 4-Blast in Iranian city kills 12, injures dozens
* "Time-bomb" explodes in crowd watching parade -official
* Officials blame militants, but no responsibility claimed
* "Sacred Defence" parades commemorate war with Iraq (Updates injured toll, adds byline, official quote paragraph 8)
By Robin Pomeroy and Ramin Mostafavi
TEHRAN, Sept 22 (Reuters) - Twelve people were killed and more than 70 injured on Wednesday when a bomb exploded among a crowd watching a military parade in northwestern Iran.
Officials blamed the blast, in the city of Mahabad in the predominantly Kurdish area near the borders of Iraq and Turkey, on "anti-revolutionary" militants backed by foreign states.
"This bomb was a time-bomb planted on a tree among the people and it went off at 10:20 (0650 GMT)," the website of state-run television IRIB quoted a military official as saying.
There was no immediate claim of responsibility for the attack on the parade, which was part of "Sacred Defence" celebrations, an annual ceremony for the Iranian military.
"Counter-revolutionary groups, by inserting themselves among the people attending the armed forces parade, showed their heinous face," said Vahid Jalalzadeh, the provincial governor of Iran's West Azerbaijan province. Continued...