Robert Fisk: A quiet Baghdad night of occasional air raid sirens and mysterious explosions

On the roof of the al-Jazeera office in Baghdad, you could hear the missile coming. It swooped down out of the clouds of smoke south of the Tigris, hissed past the office and disappeared over the old Ahrar bridge. "Was that what I think it was?" the anchorman asked me down the line from Doha. Ah yes, indeed. It was one of those days. A few minutes later, chatting to the al-Jazeera staff in their waterfront villa, an old colonial home with wooden bannisters and beautifully crafted blue-and-white patterned floor tiles, came the sound of supersonic jets.

We looked at each other with that special intensity that members of the most successful Arab television channel do when they smell danger. Only 18 months ago, the Americans sent a cruise missile into al-Jazeera's office in Kabul, an attack for which the United States neither apologised nor explained. But Tony Blair was attacking the station last week for showing videotape of two dead British soldiers in Basra and, only a few days ago, who should turn up at al-Jazeera's Baghdad office but Taiseer Alouni, former manager of the Kabul office who was lucky to avoid the earlier cruise attack.

There was a shattering explosion, the villa shook and the station's duty reporter shouted "To the roof!" It tells you a lot about Baghdad – and al-Jazeera – that while sane men and women would head for the basement, they climb the stairs to look. Sure enough, a blast of grey smoke was funnelling into the air on the other side of the nearest bridge, speckled by a barrage of exploding anti-aircraft shells. Another day, then, in the modern history of Baghdad.

It had been a "quiet" night. The word has to be used loosely because there are no silent nights here, just long evenings of occasional air-raid sirens and mysterious explosions whose provenance is sometimes, and often never, discovered. Before dawn, the long rumble of B-52 raids far out in the desert reminds Baghdadis that the Americans are creeping nearer. Even after dawn yesterday, the USAF and the RAF had not finished. It was time to smash up a few more telephone exchanges.

Sure enough, the switching station opposite the Saddam medical centre was missiled out of existence. So was a larger exchange near the river. As usual, the blast broke open a dozen civilian homes and devastated shops, a shoe store, a computer service and Abu al-Harith's Take Away. A front gatepost carried the words: "The home of Abdulrahman Makhles Akhaldi, No 17." The house appeared to be deserted but if Mr Makhles returns, he will find only a couple of rooms still standing.

Baghdad is also a city of rumours, sometimes confirmed, often tantalisingly obscure. The Iraqi army has announced the arrival of Arab volunteers "seeking heaven", who have arrived from every Middle Eastern country to fight for Iraq. I would have doubted all this had I not met on Saturday three serious young men, all wearing leather jackets and khaki trousers and black berets who informed me, seriously and with the sincerity of youth, that they intended to fight and if necessary die in Iraq. One was Palestinian, the other two Syrian, the first explaining to me that he was inspired by patriotism for the "pan-Arab cause" and by God.

Two more American aircraft have been shot down, the Iraqi army claimed. Again, scepticism is an essential response, as it is to more and more statements by the Anglo-American forces. Then there's the Baath Party official I meet as the American jets were sweeping back over Baghdad last night. "We shot down a plane over the Tigris and I saw the pilot bail out," he tells me.

He was from the Emirates, he was an Arab. When he landed, the people heard he was an Arab and started to beat him. He said he had an American female co-pilot who had also bailed out. She was captured later. True or false? Why on earth should Arabs be flying over Iraq in an American plane? Or was the pilot, if the story bears any relation to the truth, an Arab-American in the US Air Force? There are other stories of a Kuwaiti pilot also captured. Now the rumour is of up to 500 American prisoners-of-war, most of them taken into custody in the Najaf area. "They will be part of a political solution, if there is any," the Baath official says. Five hundred, I ask in disbelief? I do not accept this. But then I never believed that, 10 days after the start of this war, the Americans and British would still be fighting for Basra and Nassariyah and Kerbala and Najaf.