As the crisis in Yemen hots up, President Ali Abdullah Saleh’s government has shut down Al Jazeera’s offices in the capital Sana’a and cancelled press accreditation for all the satellite-TV channel’s staffers.

It may now be harder to get a clear picture of what’s going on.

The crackdown on the Qatar-based news service, which showed graphic footage of last week’s shooting of 52 demonstrators by pro-government gunmen, follows an attack on Al Jazeera’s bureau just two days ago.

According to Al Jazeera, 20 armed men smashed open the front door of its offices in the early hours of Tuesday and seized the main satellite uplink, plus computers, cameras and closed-circuit surveillance cameras.

Three days before that, Al Jazeera had asked Yemen’s Ministry of the Interior to provide security for the bureau and its staff, in the face of repeated threats to its journalists.

Instead, Saleh’s government decided to shut them down, no doubt in anticipation of more blood on the streets in coming days. Over the weekend security forces seized some of Al Jazeera’s equipment and kicked two of the network’s correspondents out of the country, accusing them of biased reporting.

The stage now seems set for a violent showdown this Friday. Yesterday, leaders of the Islamist opposition (which includes “Socialists and Nasserites”) called for a march on the presidential palace in Sana’a after prayers.

“Friday will be the ‘Friday of the March Forward’, with hundreds of thousands of people,” opposition spokesman Mohamed Qahtan told Al Jazeera, in a direct warning to Yemen’s dictator. “We will arrive where you are and we will remove you.”

“We will creep to the presidential palace with open chests and you [Saleh] can kill whatever you like to kill. We don’t accept any mediation or dialogue or any other solutions. Our main demand is ousting Saleh and his sons,” said Qahtan.

Saleh’s response to the growing threat to his rule and the chorus of calls for him to go has been to declare a 30-day state of emergency.

Yesterday, some 3000 protesters were out on the streets in Sana’a with placards saying “No to emergency rule, you butcher!” Others were selling T-shirts saying “I am a future martyr”.

In anticipation of more violence, the British Foreign Office has started withdrawing embassy staff from Sana’a and foreign oil companies have begun evacuating workers.

Meanwhile, in Syria, the protest movement finally appears to be gaining some traction.  At least 15 people are believed to have died yesterday as President Assad’s security forces opened fire on crowds gathered outside the Omari mosque in the southern city of Daraa.  Journalists are not being allowed into the city, which has seen a week of protests and is now full of police and troops, and those who have tried to get in have had equipment confiscated by police.