Hundreds of thousands of displaced Pakistanis are fleeing an embattled tribal region in the country's north where the army is clashing with militants, officials said.

At least 307,501 former residents have escaped North Waziristan, registering at numerous checkpoints along the Afghan border, Arbab Muhammad Arif, the administrative head of seven tribal regions on the border, told the Associated Press.

The mass exodus was prompted when Pakistani forces launched a long-awaited military operation last weekend against Taliban and Uzbek militants who had for many years been using the ethnic Pashtun region as a base.

The assault essentially ended Pakistan's chances of further dialogue with the militants, who have been working for years to overthrow the Pakistani government and establish a Sharia-based caliphate, resulting in the deaths of tens of thousands of civilian and army forces in the area.

"Our valiant armed forces have been tasked to eliminate these terrorists regardless of hue and color, along with their sanctuaries," the Parkistan army said in a statement. "With the support of the entire nation, and in coordination with other state institutions and law enforcement agencies, these enemies of the state will be denied space anywhere across the country."

The operation, involving troops on the ground, artillery and helicopter gunships, came days after the attack on Karachi airport on June 8, which killed 38 people. It was also announced hours after Pakistani air strikes targeting militant hideouts killed at least 80 insurgents.

Around 40,000 troops were deployed for the operation, adding to the 40,000 already present in the region, a military official told Reuters, and the Pakistan army claims it has killed at least 262 militants and torn down their hideouts so far.

Thousands of people have begun to flee Pakistan’s North Waziristan tribal district. Credit: Radio Free Europe/Radio Liberty

It is not known whether civilians have been harmed or killed in the crossfire, but as many as 62,000 immediately fled the mountainous region to other parts of Pakistan in anticipation of further violence. The rest moved out after Wednesday when the curfew imposed by Pakistan authorities was relaxed.

At least 25,242 families are included among those who have left the area, Arif said, adding they have been provided with food, drinks and 5,000 rupees per family (approximately US$50). The army also said in a statement that its soldiers would each donate a day's worth of food and pay to assist the displaced people.

Pakistani authorities, fearing that the militants may try to escape along with civilians, have sealed off the border with neighboring Afghanistan. The relaxed curfew conditions are set to remain until Sunday according to Arif, who anticipates at least another 100,000 people to leave the region.

On June 14, the country's defense minister defended Pakistan's decision to establish military control over the country's north, despite fears that the operation will spark a violent and bloody backlash.

"We as a government tried our level best to resolve this crisis through dialogue," the defense ministry said in a statement. "We were frustrated through attacks on innocent Pakistanis and damage to national assets. This operation will continue until the surrender or elimination of the enemy."

Previously Pakistani Prime Minister Nawaz Sharif, had refrained from engaging in direct military warfare with the Pakistani Taliban, and had sought instead to engage in a policy of negotiation.

The Islamic Movement of Uzbekistan (IMU) and the Pakistani Taliban's joint claims of responsibility for the Karachi airport attack seemed to mark a turning point for Pakistanis, prompting renewed US and Pakistani drone strikes against militant positions.

Security has been ramped up in major cities across Pakistan following recent militant assaults on Karachi. Credit: Radio Free Europe/Radio Liberty

Most of those who died in the air strikes last weekend were Uzbek militants, Pakistani military officials told the Associated Press.

The IMU, is a militant group who initially sought to overthrow the Uzbek government and set up an Islamic state under Sharia, but later expanded its ambitions to encompass Central Asia as a whole.

It has been using North Waziristan as a base to attack NATO and Afghan troops, prompting US action.

Pakistan is currently hosts more refugees within its borders than any other country, according to a United Nations report released on Saturday. Many of the 1.6 million refugees in the country have fled from Afghanistan.

Pakistan is currently the biggest host nation, with 1.6 million refugees within its borders, according to a new UN report. Credit: Radio Free Europe/Radio Liberty