A terrorist grenade attack (15 thrown, of which only 9 exploded) in Sanaa, Yemen, on April 15 caused few casualties, but suggests that the insurgents operating in the north may be trying to expand their operating area southward. In addition to increasing security in the capitol, the government is already initiating tighter security measures for the annual "Unity Day" observances, to be held on May 22, which commemorate the unification of Northern and Southern Yemen a decade ago. The fighting in the north has died down, with over a hundred dead and several hundred arrested. This has not resolved the deep religious and cultural differences between the tribal north and urban south. That over simplifies the situation a bit, for every Yemeni feels an attachment to a tribe or clan. But in the north, tribal affairs play a much larger role in ones life. Religion is another major factor, with Islamic radicalism still very popular. Again, this is more the case in the north. The government has shut down 1,400 religious schools that were mainly brainwashing kids to become Islamic warriors and terrorists. The government believes there are still over 300,000 children being indoctrinated in illegal underground religious schools. The fighting between the northerners and southerners has been going on for thousands of years, and it's not just a result of the current wave of Islamic radicalism. But the Islamic radicals are involved this time around, and that makes it important on an international basis. The better educated, and wealthier, southerners are keen on keeping the northern tribes at peace, and have joined in the war on terror to help make that happen.