slamist militants have seized key buildings of Mosul, effectively taking control of Iraq's second largest city.

Overnight, hundreds of men armed with rocket-propelled grenades, sniper rifles and machine-guns seized the provincial government's offices.

They also destroyed several police stations before overrunning the airport and army's operations headquarters.

Iraq's parliamentary speaker said security forces personnel had fled and called for reinforcements from Baghdad.

In the past week, the jihadist Islamic State in Iraq and the Levant (ISIS) and its allies have carried out major attacks on cities and towns in western and northern Iraq, killing scores of people.

'Afraid'

The BBC's Jim Muir in Beirut says militants from ISIS have been informally controlling much of Nineveh province for months, imposing tolls of the movement of goods and demanding protection money from local officials.

After five days of fierce fighting, they took control of key installations in Mosul, which has a population approaching two million in normal times.

On Monday, Nineveh Governor Atheel al-Nujaifi made a televised plea to the city's residents, calling on them to resist.

"I call upon the men of Mosul to stand firm in their areas and to defend them against the strangers and to form public committees in their districts to help their people and to protect their areas," he said.

But Mr Nujaifi fled shortly before the provincial government's headquarters fell to the onslaught late on Monday night.

On Tuesday, several residents told the Associated Press (AP) news agency that black flags associated with jihadist groups were flying from buildings and that the militants had announced over loudspeaker that they had "come to liberate Mosul and would fight only those who attack them".

"The situation is chaotic inside the city and there is nobody to help us," said Umm Karam, a government employee. "We are afraid."

Many police stations are reported to have been set on fire - local TV stations showed pictures of plumes of smoke rising over the city - and hundreds of detainees were set free.

An interior ministry official admitted that police and soldiers had fled after removing their uniforms, telling the AFP news agency: "The city of Mosul is outside the control of the state and at the mercy of the militants."

Osama al-Nujaifi, the speaker of parliament and brother of Nineveh's governor, said he had asked the US ambassador for help.

He called on the Iraqi government and Kurdistan Regional Government to urgently send reinforcements to Mosul to "fight the terrorists", whom he said had seized military hardware, including helicopters.

Meanwhile, the Turkish consulate in Mosul confirmed reports that 28 Turkish lorry drivers had been abducted by militants in Nineveh.

Our correspondent says the assault is another massive challenge to the incumbent Shia Prime Minister, Nouri Maliki. Mosul is a mainly Sunni city, and it is long chafed under his rule, he adds.

It comes as the Iraqi authorities struggle with a surge in sectarian violence that killed almost 800 people, including 603 civilians, in May alone, according to the UN. Last year, more than 8,860 people died.

Parts of Ramadi, the capital of Anbar province, and much of the nearby city of Falluja have been under the control of ISIS and its allies since late December, something that Mr Maliki has been unable to reverse.

Also on Tuesday, at least 15 people were killed and 27 wounded in a bomb attack on a funeral in the central city of Baqouba, officials told AP.

(BBC)