You do realize that's not his actual twitter account, right? Please tell me you know that. The account has only 716 followers, is not verified, and nothing on his official site (yes, he has an official site) says anything about him "tweeting". Plus most of the messages are apparently from a... uh... "fan" of his, as most of the tweets begin with "The Supreme Leader's View of..." and link to some article.

Amusingly, there appear to be MULTIPLE fake Khameneis on twitter:

http://twitter.com/sayyidkhamenei

Although I must admit, the thought of Mr Supreme Leader himself sitting down and tweeting about Justin Bieber is hilarious.

Not his real twitter account. Get this irresponsible pseudo-news off of here before you cause an international incident.

This is seriously irresponsible journalism, FP.

Not a real twitter account. Yeah, this is the kind of gossip that make wars.

First, it's not his actual Twitter account. I could go on and register a name like "Iamtherealahmedinajad" and tweet crap about other countries, would I get the same coverage.
Second. Even in the hypothetical situation that the tweet was real, I don't see how this would be cause for any outrage. The world press and US/Istaeli politicians continuously make statements like "Iran is a threat to humanity", "Iran shall be attacked", etc. You even write articles about how a military attack on Iran would work.

http://english.khamenei.ir/
"Those who are resisting and suffering innocently in the occupied Palestinian lands are the only ones offering hope about the freedom of Palestine and the annihilation of the usurping Zionist regime."
Waiting to hear how the Ahmadinejad apologists around here will explain this (you know, the same ones who think it's ok to hang gay people and stone adulterers to death).