Iran has forcefully denied that it shot down a Ukrainian jetliner, killing all 176 people on board, following the growing consensus among Western powers that the plane was hit by a surface-to-air missile near Tehran. On Thursday, Western leaders said their intelligence showed the plane appeared to have been unintentionally hit by a missile hours after Iran launched a series of strikes on two U.S. bases in Iraq. Speaking Friday, Ali Abedzadeh, the head of Iran’s national aviation department, said: “What is obvious for us, and what we can say with certainty, is that no missile hit the plane... If they are really sure, they should come and show their findings to the world.” Hassan Rezaeifar, the head of Iranian investigation team, warned his investigation could stretch into next year. State news reported Friday that the Iranian government has invited Boeing to take part in the investigation in light of the new allegations. The country had initially said it would not allow the aviation company to take part in the probe.