The Islamic State of Iraq and the Levant renamed itself simply the Islamic State (IS) and declared its shadowy frontman the leader of the world's Muslims, in a clear challenge to al-Qaeda for control of the global jihadist movement.
Iraqi forces meanwhile pressed a counter-offensive Monday against executed dictator Saddam Hussein's hometown of Tikrit, one of a string of towns and cities overrun by IS-led fighters in a swift advance that left more than 1,000 people dead, displaced hundreds of thousands and piled pressure on Prime Minister Nuri al-Maliki.
IS announced yesterday it was establishing a "caliphate" -- an Islamic form of government last seen under the Ottoman Empire -- extending now from Aleppo in northern Syria to Diyala province in eastern Iraq, the regions where it has fought against the regimes in power.
In an audio recording distributed online, the group declared its chief Abu Bakr al-Baghdadi "the caliph" and "leader for Muslims everywhere". Henceforth, the group said, he is to be known as "Caliph Ibrahim" -- a reference to his real name.
The caliphate is "the biggest development in international jihad since September 11", said Charles Lister of the Brookings Institution in Doha, referring to the al-Qaeda attacks on the United States in 2001.
"It could mark the birth of a new era of transnational jihadism... And that poses a real danger to al-Qaeda and its leadership," he said, adding that IS, with members in many countries, is the richest jihadist group.