By Syed Shoaib Hasan
BBC News, Islamabad
"Only God can help us now."
The information minister comforts the brother of a woman inside the mosque
Former Pakistani Prime Minister Chaudhry Shujaat Hussain was speaking to journalists in Islamabad after last-minute negotiations aimed at ending the siege of the controversial Red Mosque had failed.
And yet, shortly before, it had all seemed to be heading for such a different resolution as government sources and Islamic scholars involved in the talks were jubilant that a deal had been reached.
One leading Islamic scholar was seen smiling and telling a TV channel that all was well and "we will tell you the good news soon".
Smiling parents were also seen, as it appeared that their week-long nightmare was at last at an end.
The sticking point, it appears, was the demand of the leader of the students inside the mosque, Abdul Rashid Ghazi, that foreign militants inside be granted an amnesty.
Shortly after Mr Hussain, the chief negotiator, spoke to the press, soldiers from the Pakistan army's Special Services Group stormed the mosque.
Ambulances head towards the mosque
They were backed by hundreds of regular troops and light artillery.
Eyewitnesses saw commandos scale the mosque walls and make their way into the compound which includes a religious school (madrassa) for women and girls.
The fiercest attacks were from the north-east and southern part of the compound.
When we reached a vantage point a kilometre from the mosque an hour after the operation started, massive explosions and heavy firing could be heard.
Reports of casualties had started to come in and initial information suggested government forces were encountering stiff resistance, particularly from the basements and the central building of the compound.
This is where the army believes the militants are holding a number of hostages. Officials say these parts of the compound could be mined, and that some of those inside the mosque could be suicide bombers.
We saw two badly wounded soldiers being whisked away in ambulances.
But journalists were being prevented from going to the hospitals to check the exact number of casualties, of whom there are said to be dozens.
Several family members of the students still trapped inside were watching the proceedings with worn and tense faces.
One man, Zahid Mahmood, broke down and started weeping inconsolably.
"My brother Sohail Ahmed was inside... I last talked to him on Friday," he told the BBC.
"He was so scared... He said that when he tried to escape the people outside would shoot at him."
Zahid said his 20-year-old brother just wanted to get out alive. As he was speaking to me, his mobile phone rang.
"It's from home," he said.
The conversation is conducted in a series of sobs and muted sounds. It is apparent the anguish is too great for words.
In the meantime the firing continued and we saw a spiral of black smoke rising snake-like from the mosque.
Smoke can be seen in the distance rising above the mosque
A helicopter appeared on the horizon. It headed in the direction of the battle before hovering briefly over the mosque.
Military spokesman Gen Waheed Arshad then made another appearance to say that the military had taken control of much of the Red mosque.
"We have cleared 70% of the area, and the remaining is the most difficult," he says.
This is where, according to him, the women and children are being held hostage.
He said the military was doing its best to save as many lives as it could.
"But we have gone in to clear the mosque and that is exactly what we aim to do."
Outside the firing and explosions started again as the fighting resumed.
Much blood has been shed and more is likely to flow as the army says it is now clearing the mosque room by room, while a small number of militants fire down from high up on a mosque minaret.
Quite how heavy the casualties are and how many are militants may take some time to establish.
All hospitals treating the injured have been closed off to media and general public, except those with injured relatives inside.
At Islamabad's main hospital, the Pakistan Institute of Medical Sciences, we were told that nine commandos and six students had been admitted. Two of the commandos later died.
At the main military hospital in neighbouring Rawalpindi, the main gates were barricaded off and we were told to leave.