US intelligence official: Iran involved in fight against IS

America's top intelligence official says Iran is involved in the fight against the Islamic State group in Iraq.

Director of National Intelligence James Clapper says Tehran has "a very robust commitment to the fight" and has people there in an advisory capacity.

In an interview broadcast Tuesday on CBS, Clapper says the Iranians have "brought in large amounts of weaponry" to Iraq.

Clapper also says Iran already has the "technical competence" to make a nuclear weapon and a decision will be up to Supreme Leader Ayatollah Ali Khamenei.

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