Islamic State fighters seized control of Iraq's biggest dam, an oilfield and three more towns on Sunday after inflicting their first major defeat on Kurdish forces since sweeping across much of northern Iraq in June.
Capture of the electricity-generating Mosul Dam, after an offensive of barely 24 hours, could give the Sunni militants the ability to flood major Iraqi cities or withhold water from farms, raising the stakes in their bid to topple Prime Minister Nuri al-Maliki's Shia-led government.
"The terrorist gangs of the Islamic State have taken control of Mosul Dam after the withdrawal of Kurdish forces without a fight," said Iraqi state television.
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The swift withdrawal of Kurdish "peshmerga" troops was an apparent severe blow to one of the only forces in Iraq that
until now had stood firm against the Sunni Islamist fighters who aim to redraw the borders of the Middle East.
The Islamic State (formerly known as Islamic State in Iraq and Syria, or ISIS), which sees Iraq's majority Shias apostates who deserve to be killed, also seized the Ain Zalah oilfield — adding to four others already under its control that provide funding for operations — and three towns.
Initially strong Kurdish resistance evaporated after the start of an offensive to take the town of Zumar. The Islamists
then hoisted their black flags there, a ritual that has often preceded mass executions of their captured opponents and the imposition of an ideology even al-Qaeda finds excessive.
The group, which has declared a caliphate in parts of Iraq and Syria to rule over all Muslims, poses the biggest challenge to the stability of OPEC member Iraq since the fall of Saddam Hussein in 2003.
Fighting for towns
On Sunday, its members were also involved in fighting in a border town far away in Lebanon, a sign of its ambitions across the frontiers of the Middle East.
It controls cities in Iraq's Tigris and Euphrates valleys north and west of Baghdad, and a swathe of Syria stretching from
the Iraqi border in the east to Aleppo in the northwest.
Iraq's Kurds, who rule themselves in a northern enclave guarded by the "peshmerga" units, had expanded areas under their control in recent weeks while avoiding direct confrontation with the Islamic State, even as Iraqi central government troops fled.
But the towns lost on Sunday were in territory the Kurds had held for many years, undermining suggestions that the Islamic State's advance has helped the Kurdish cause.
Witnesses said Islamic State fighters were also trying to take control of the town of Rabia near the Syrian border and
were engaged in clashes with Syrian Kurds who had crossed the frontier after Iraqi Kurds withdrew.
The latest gains have placed Islamic State fighters near Dohuk Province, one of three in the autonomous Kurdish region, which has been spared any serious threat to its security while war raged throughout the rest of Iraq.
Since thousands of U.S.-trained Iraqi soldiers fled the Islamic State offensive, the Kurdish fighters were seen
alongside Shia militia to the south as the main lines of defence against the militants, who vow to march on Baghdad.
By calling into question the effectiveness of the Kurdish fighters, Sunday's advances may increase pressure on bickering Iraqi leaders to form a power-sharing government capable of countering the Islamic State.
Two people who live near Mosul Dam told Reuters Kurdish troops had loaded their vehicles with belongings including air
conditioners and fled.
Islamic State fighters attacked Zumar from three directions in pickup trucks mounted with weapons, defeating Kurdish forces that had poured reinforcements into the town, witnesses said.
The Islamic State later also seized the town of Sinjar, where witnesses said residents had fled after Kurdish fighters put up little resistance. It was not immediately clear why the Kurds, usually known as formidable fighters, pulled back without a fight.
On its Twitter site, the Islamic State posted a picture of one of its masked fighters holding up a pistol and sitting at the abandoned desk of the mayor of Sinjar. Behind him was the image of a famous Kurdish guerrilla leader.
In a statement on its website, the Islamic State said it had killed scores of peshmerga, the Kurdish fighters whose name means "those who confront death". Those deaths could not be independently verified.
"Hundreds fled leaving vehicles and a huge number of weapons and munitions and the brothers control many areas," the Islamic State statement said. "The fighters arrived in the border triangle between Iraq, Syria and Turkey."
The Islamic State has systematically blown up Shia mosques and shrines in territory it has seized, fuelling levels
of sectarian violence unseen since the very worst weeks of Iraq's 2006-2007 civil war.
The group has stalled in its drive to reach Baghdad, halting just before the town of Samarra, 100 km north of the capital.
Islamic State advances
The Islamic State has been trying to consolidate its gains, setting its sights on strategic towns near oil fields, as well
as border crossings with Syria, so that it can move easily back and forth and transport supplies.
So far, the Islamic State is not near the major oilfields of the northern city of Kirkuk, which were seized by the Kurds in the chaos that followed the Islamic State's advance. It controls part of a pipeline from Kirkuk to Turkey which has been idle for months because of its attacks in the area.
The Islamic State has capitalized on Sunni disenchantment with Maliki by winning support or at least tolerance from some more moderate Sunni communities in Iraq that had fought against al-Qaeda during the U.S. "surge" offensive of 2006-2007.
Maliki's opponents say the prime minister, a Shia Islamist who is negotiating to try to stay in power for a third
term after an inconclusive parliamentary election in April, is to blame for galvanizing the insurgency by excluding Sunnis from power. Kurdish leaders have also called for Maliki to step down to create a more inclusive government in Baghdad.
The Kurds have long dreamed of their own independent state, an aspiration that has angered Maliki, who has frequently
clashed with the non-Arabs over budgets, land and oil.
In July, the Kurdish political bloc ended participation in Iraq's national government in protest against Maliki's
accusation that Kurds were allowing "terrorists" to stay in Arbil, capital of their semi-autonomous region.