By Syed Shoaib Hasan
BBC News, Dera Ismail Khan, South Waziristan border
Fleeing civilians have made the town of Dera Ismail Khan their destination
For Pakistan's much-maligned security forces, this offensive in South Waziristan is a chance to prove to the world how committed they are in the battle against militancy.
"There are bombs going off everywhere - you must tell the world what is happening," Sher Gul, a terrified resident of Tiarza in South Waziristan told the BBC after arriving in Dera Ismail Khan.
"My house was destroyed and many people in my village have been killed."
The fighting in Tiarza is part of the Pakistan army's operation in South Waziristan.
It has been called the most significant battle against militancy in the region.
It is also the end of a long wait for the rest of the world - and especially the United States. The authorities there waited with bated breath as Pakistan's leadership took its time to make up its mind on the issue.
But things probably came to a head with the recent string of deadly attacks which have rocked the country in recent weeks.
These seem to have galvanised the leadership and forced the issue.
Escape routes blocked
Early signs were clear as we arrived in Dera Ismail Khan on Friday. All mobile phone networks within the district were blocked.
We later learned that networks had also been blocked in Bannu and the Lakki Marwat districts, both near the Waziristan region.
These are likely routes by which civilians who live in South Waziristan would attempt to leave the region but it could also be an escape route for militants.
We saw army convoys moving from the city of Dera Ismail Khan to Tank.
The town is known as the gateway to South Waziristan and has long been the launching pad of any military adventure in that region.
Reports started coming in early on Saturday that thousands of troops had started moving towards the Taliban-controlled tribal belt from three directions.
This was evident while we were travelling on the road.
Several military convoys carrying troops and ammunition were shepherded in the direction of South Waziristan by security details.
The going was slow. Civilian vehicles are not allowed to pass a military convoy here because of fears of suicide car bombs.
There have been several such attacks on this road and we therefore chose to keep our distance.
There were also checkpoints where we had to stop for passing convoys or to prove our identity.
Pakistan has been on alert after a wave of bombings hit cities last week
Grim-faced soldiers manned them warily regarding every vehicle as if it were a ticking bomb.
As a result, instead of the half-hour drive, it took us two frustrating hours to reach the border of South Waziristan.
During this time, we also passed several vehicles laden with refugees and their families heading towards Dera Ismail Khan.
People hung off vehicles, clinging to whatever part of it they could hold on to to get a ride into town.
Usually bustling with activity in the afternoon, there was a distinct air of tension as we drove through the main market.
Troops were omnipresent and traffic in the town was thin.
We headed in the general direction of the Frontier Corps compound in Tank, right at the edge of town.
Just past it is a dilapidated security checkpoint on a road heading west.
This is the start of South Waziristan, and the road heads to Jandola, the region's first major town.
It is from this point that most of the civilian population of South Waziristan left the region.
We hoped to find some more weary souls trudging in from the war zone but discovered that the route had been shut down by the military.
Before we left the town, local administration officials told us that the fighting was centred in Tiarza, Makeen and Spinkai Raghzai.
According to them, there have been dozens of casualties on both sides as the militants put up fierce resistance.
"The terrain will play a great factor and the militants have always used it to their advantage," says one official.
"For the ground troops it will be tough going as the cold wave sweeps in."
In Dera Ismail Khan, though, we found many people lining up to register their newly-displaced status.
FORCES IN WAZIRISTAN
Pakistan army: Two divisions totalling 28,000 soldiers
Frontier Corp: Paramilitary forces from tribal areas likely to support army
Taliban militants: Estimated between 10,000 and 20,000
Uzbek fighters supporting Taliban: Estimates widely vary between 500-5,000
"We are caught between the government and the Taliban," says Mohammad Roshan, a South Waziristan resident.
"We have lost everything and are stuck here till the fighting ends."
For Pakistan's government, this is the real test.
The militants know that the state cannot afford a prolonged operation.
As winter approaches, the government needs a rapid conclusion to this campaign.
Anything else could have lasting consequences for the future of militancy in the region.
For the security forces this is a once-in-a-lifetime chance to finally bury the militant threat which has returned to haunt them.