Sean Penn has  released what MTV is calling  "a measured response" to the "harsh lyrical attack" from  Wyclef Jean as the two continued their public rap battle over 'Clef's failed bid to run for the presidency of Haiti.  More details of Sean Penn's statements against Wyclef on the other side.

"Mr. Jean is clearly unfamiliar with the physical demands put upon volunteers in Haiti,"  "As aid workers there, the notion of depleting the body's immune system thru the use of illicit drugs is ludicrous."

The letter was in part a response to some new lyrics Jean threw down at Hot 97's On Da Reggae Tip concert in New York on Friday. He switched up the verses to his 2004 song "President" in order to take aim at Penn and his former Fugees bandmate Pras, who both questioned Wyclef's fitness to run earthquake-ravaged Haiti.

"I got a message for Sean Penn: Maybe he ain't see me in Haiti because he was too busy sniffing cocaine," Jean sang at the show on Friday, adding, "I got a message for Praswell, even though you don't want to support me, I got love for you, even though you only kicked eight bars in the Fugees."

Penn, who has lived in a tent in Haiti since just after January's earthquake, also used his statement to explain to 'Clef exactly what he's been doing on the ground and why the lyrical roundhouse failed to connect.

"More specifically, J/P Haitian Relief Organization (a.k.a. JPHRO) has a ZERO tolerance policy for any and all illegal drugs," Penn's statement said, referring to the non-governmental organization the actor co-founded to help the island just hours after the quake hit. "As the leader of this organization, Sean Penn has not only set this policy, but adheres to it. That Mr. Jean would make such a false accusation is reckless and saddening, but not surprising."

When Jean spoke about his plans to run for Haiti's head of state on CNN's "Larry King Live" in August, Penn, who was also a guest on the show, expressed concerns about the singer's motivations for seeking political office.

"Right now, I worry that this is a campaign that is more about a vision of flying around the world, talking to people. It's certainly not one of the youth drafting him. I would be quite sure that this is an influence of corporations here in the United States and private individuals that may well have capitalized on his will to see himself flying around the world," Penn said.

The actor also wrote in a Huffington Post column that despite Jean's public support for the island nation, the MC wasn't around during critical moments after Haiti's devastating January earthquake.

"I was there for those six months after the earthquake and so many of us on the ground wondered where he was when that kind of attention was so necessary and absent, and why he was NOT helping to keep this desperate situation in the news," he wrote. "None among us felt or expressed anger toward it, but rather a universal sadness for his silence, as he is America's most admired cultural link to Haiti."