Tehran is open to the possibility of working with the United States to support Baghdad, the senior official said.
Many said they panicked after hearing Iraqi army soldiers had abandoned their posts, sure it meant that heavy shelling to drive out the insurgents would follow.
The militants have already captured two provincial capitals this week -- Tikrit in Salaheddin province and second city Mosul in Nineveh.
Iraqi Foreign Minister Hosyhar Zebari acknowledged the security forces that Washington invested billions in training and equipping before withdrawing its own troops in 2011 had simply melted away.
The exodus from the mountainous North Waziristan has been hastened by the Taliban's all-night siege of Karachi airport this week, which all but destroyed a tentative peace process
Since 2011, Washington has agreed to provide the Iraqi government $15 billion in military equipment and training, but many of the critical elements have yet to be delivered.
The strikes are the first in the nuclear-armed South Asian nation since an attack in December last year in which three suspected militants were killed.
Sixteen militants were killed in in two US drone strikes within last 24 hours in Pakistan's restive tribal region, ending a five-month hiatus.
The request has been turned down in the past, but Washington is now weighing possibilities for more military assistance to Baghdad, including drone strikes
"At this point, I would not be prepared to vote for stopping them (drone strikes) in Pakistan, but I am open to arguments," Congressman Adam Smith, Ranking member of powerful House Armed Services Committee, said
The only way to save Pakistan is to battle terrorism, PPP leader Bilawal Bhutto Zardari said today as he lashed out at politicians like Imran Khan whom he accused of backing militants.
While American security experts say the drone strikes target only terrorists, human rights activists claim a number of civilians are also killed.
Among the dead at the Defense Ministry complex, which also houses a military hospital, were soldiers and civilians, including seven foreigners — two Germans, two Vietnamese, two Filipinos and one Indian, according to the Supreme Security Commission.
The United States has temporarily halted shipment of its "retrograde cargo" from Afghanistan in view of the anti-America demonstrations in Pakistan which it believes puts at risk the safety and security of the truckers.
A contempt of court petition has been filed against Prime Minister Nawaz Sharif and the federal authorities in the Peshawar High Court over the government’s failure to end US drone strikes.
Hakimullah Mehsud, who is believed to have been behind a failed car bombing in New York's Times Square as well as brazen attacks inside Pakistan, had a reputation for being particularly ruthless.
Intelligence officials say the leader of the Pakistani Taliban was one of three people killed in a suspected U.S. drone strike
Pakistan has strongly denied a UN report that members of its government had given consent to controversial drone strikes.
Sharif concluded a four-day official visit to Washington on Wednesday. He repeatedly raised the issue of missile attacks by CIA-operated drones during his meetings with President Barack Obama and several senior officials.
President Obama and Prime Minister Sharif held wide-ranging discussions at the White House today about the importance of a US-Pakistan partnership built on a foundation of mutual interest and respect.