The humanitarian crisis caused by the Houthi conflict in northern Yemen is rapidly getting worse. Yesterday the UN High Commissioner for Refugees, Andrej Mahecic, announced revised estimates for the number of people displaced by the fighting – putting the total at 200,000. This is an increase of 25,000 since last month's estimate.

The camps set up by aid agencies are having difficulty coping with the influx. Al-Mazrak 1 camp in Hajjah is currently sheltering at least 21,000 people – more than double its original capacity. “There are now huge makeshift sites along the roads close to the al-Mazrak camps. Shelling can be clearly heard in this area and it is a constant reminder of the ongoing conflict in the area,” Mahecic said.

The Yemen government said yesterday its forces had killed 19 Houthi rebels and arrested 25 more in the old city of Saada, but gave few details beyond saying the operation "achieved all of its goals". The government has been claiming for weeks that it is on the verge of clearing the city of rebels.

Meanwhile, Saudi Arabia – which officially joined the war early in November and announced the imminent ending of "major operations" last month, says four more of its soldiers have been killed in clashes with rebels in the border area. 

According to Prince Khaled bin Sultan, the assistant defence minister, 82 Saudis have been killed so far and 21 are missing. Late last month, 470 others were said to have been wounded.

The number of Saudi troops taking part has not been disclosed, but this is clearly a very high casualty rate during the nine weeks of fighting. For comparison, Britain lost 105 soldiers in Afghanistan during the whole of last year, which was by far the worst year since it sent troops there.

• An unusually good article on the Houthi conflict – "A war with a life of its own", by Patrick Martin – appeared in the Globe and Mail yesterday. In particular, it discusses the negative role played by President Salih's kinsman, General Ali Mohsen al-Ahmar.

Posted by Brian Whitaker, 13 January 2010.