Osama bin Laden’s top lieutenant has released an Internet video calling on Iraqi insurgents to remain strong in the fight against Americans and praising the leadership of Abu Musab al-Zarqawi, the Jordanian militant who directs Al Qaeda’s operations in Iraq. An introductory title on the video indicates that the lieutenant, Ayman al-Zawahiri, recorded the message last November, months after he is believed to have written a 6,000-word letter asking Mr. Zarqawi to refrain from slaughtering Shiites. In recent months, perhaps in response to the letter, Mr. Zarqawi has not personally taken responsibility for any major attacks in Iraq. Full Story