Dr Khan works at the Federal Government Services Hospital in Islamabad, around 850 metres from the Red Mosque that was stormed by government troops early on Tuesday morning.
He describes the situation there since last Tuesday when the hospital was put on red alert and started receiving casualties.
Dr Khan: I can see the smoke rising above the Red Mosque
We were in the operating theatre, totally oblivious to what's been happening in the outside world, when we received a government order to discharge the whole hospital.
All 700 beds were cleared in 20 minutes. We only left some of the patients with heavy complications. We've been on red alert since then and we've been treating injured people for days.
We started receiving casualties since Tuesday, the first day. Our first casualty was a ranger officer, he was shot dead. Most of the others were girls suffering from suffocation or from tear gas. We had around 150 to 200 on the first day only. They were all fine in the end.
We have so far received 26 gunshot victims, but of course this is only in our hospital and the real number is much higher.
There is a lot of secrecy, we don't know why our hospital was sealed
Yesterday I was on night duty. I was having a quick nap, when I was woken up at 0420 (2320 BST) by a huge blast. The windows were trembling.
Since then there's been non-stop firing of heavy machine guns. You can tell by the sound that there's been very heavy fighting. We also hear rocket-propelled grenades. Since this morning they have been using heavy equipment.
We haven't received any injured from the armed forces. They are being taken by four helicopters from a nearby sports stadium to a special military hospital 30km from here. Nobody has access to that hospital and nobody knows how many casualties there are.
We've heard that orders have been passed that any members of the media who are in the mosque area will be shot at. We've had loads of journalists standing outside the hospital for days. This morning I saw a small group of journalists and cameramen being kicked and pushed by security forces.
The strange thing is that our hospital was sealed at 0900 on Tuesday morning (0400BST) and we haven't received any injured today. All the ambulances are now directed to which hospital to go by the military.
They must have something in mind for our hospital. There's probably a special plan in place and our hospital is probably being kept as a last resort.