"The rocket firing at the ancestors of monkeys and pigs from the south of Lebanon was only the start of a blessed in-depth strike against the Zionist enemy... All that was on the instructions of the shaikh of the mujahidin, Osama bin laden, may God preserve him," said the voice attributed to al-Zarqawi.
The tape was found on Sunday on the website normally used by his group, the Organisation of al-Qaida in Mesopotamia, which had claimed responsibility for the rockets in an online statement on 29 December.
"This commendable feat came in application by the mujahidin of the oath by fighter Shaikh Osama bin Laden, emir of the al-Qaida network, may God preserve him," al-Zarqawi said, referring to repeated statements by bin Laden that the Israelis should not enjoy security as long as Muslims were not safe.
Israel had carried out an air strike against a base of a Syrian-backed Palestinian group on the southern outskirts of Beirut the previous day in retaliation for cross-border Katyusha rocket attacks on northern Israel.
40,000 crusader casualties
Al-Zarqawi also said his fighters had carried out nearly 800 operations against "the crusader forces" since the invasion of Iraq, putting "crusader" casualties at around 40,000 soldiers.
"Since the start of mujahidin operations after the fall of the
Baathist regime and until today, nearly 800 martyr operations aimed at crusader targets and military convoys have been carried out," he said.
"We estimate casualties among the adorers of the Cross in Iraq at no less than 40,000 soldiers.
Bin Laden says Israelis should not
enjoy security since Muslims do not
"That's why they [the Americans] asked for help from the Arab League, represented by its secretary-general Amr Moussa, and called for the Cairo meeting." This was a reference to Arab countries that took part in the November meeting dedicated to Iraq under Arab League auspices.
The Iraqi leaders who participated in the Cairo meeting agreed on a process for national conciliation, calling for a calendar for withdrawal of foreign forces and the release of detainees who had not been charged.
Al-Zarqawi also hit out at the Sunni Muslim Iraqi Islamic Party for having taken part in the general elections last month and called on it to renounce such actions.
"We call on the Islamic Party to abandon the road to perdition on which it has embarked and which threatened to cause the loss of the Sunni community," al-Zarqawi said. He said that the party "should have called the people to jihad".
The Iraqi al-Qaida leader then laid down two conditions for giving up the jihad: "First, chase out the invaders from our territory in Palestine, in Iraq and everywhere in Islamic land.
"O young Muslims everywhere in the world, and in particular in the neighbouring countries [of Iraq] and in Yemen, I recommend jihad to you... O nation of Islam, America is today drawing its last breath"
Abu Musab al-Zarqawi,
al-Qaida's leader in Iraq
"Second, install sharia Islamic law] on the entire Earth and spread Islamic justice there ... The attacks will not cease until after the victory of Islam and the setting up of sharia.
"O young Muslims everywhere in the world, and in particular in the neighbouring countries [of Iraq] and in Yemen, I recommend jihad to you ... O nation of Islam, America is today drawing its last breath."