After being set back by the increased US military presence in Iraq, Islamists are focussing on Yemen as a new territory for their operations, according to experts. In recent months Yemen has seen a series of attacks on security services and oil installations claimed by groups linked to Al-Qaeda, with two attacks on US targets in the past six months. On September 17, an attack on the US embassy in Sanaa left 18 dead, including an Islamist militant who claimed responsibility for the attack. Experts say the attacks represent both the resurgence and the resilience of Islamist terrorism which, in the years following the September 11, 2001 attacks in the United States, appeared to have quietened. In the vast and mountainous country with pockets beyond state control, Al-Qaeda followers -- under a renewed and younger leadership -- are seeking out the opportunity to create new cells. "...from September 2001 to November 2003, the Yemeni government did a very good job, along with US help, on splintering the leadership of Al-Qaeda," said Gregory Johnsen, a professor at Princeton University. Until February 2006, there was very little Al-Qaeda activity in Yemen and "with the war in Iraq, many of the younger individuals who wanted to go off and fight were able to do that," said Johnsen. That month, the escape of 23 Al-Qaeda members from a prison run by the Yemeni secret service unleashed trained Jihadists into the country. "...they worked harder to re-establish the infrastructure of the organisation within Yemen , and they have been helped by some of the returnees from Iraq," said Johnsen. According to an editorial published September 20 in the daily Arab News, the attack in Sanaa "shows that despite the government's efforts, militants, including those from Al-Qaeda, are still active in the country and can hit where they want". Yemen is attractive to the Islamist militants for a variety of reasons, said Nabil al-Soufi, editor-in-chief of the website NewsYemen. For Al-Qaeda, Yemen provides a "fertile environment" with a lack of state control in "the arid and mountainous regions of the country, where Al Qaeda can establish training camps, without anyone noticing," he said. Yemen 's proximity to Saudi Arabia also plays a role, according to Dominique Thomas, an expert in radical Islam at France's Graduate Center for Social Sciences (EHESS). "If Yemen has become more important for militants, it's also due to ... the fierce repression that took place in Saudi Arabia" from where many of the jihadists spilled over, said Thomas. Along with other experts in the field, Thomas said the Yemeni government does not view Islamist militants as a vital threat and has on several occasions chosen to enter into agreements with them rather than to fight them face on. "Yemeni authorities have always priviledged their relations with the Islamists and tribes so as to strenghten their authority against the main threat, people from the south and Shiites from the north," said Thomas. Johnsen suggested the authorities have in fact prevented even more attacks from taking place. The "government has made several agreements with some individuals within Al-Qaeda in order to get them not to carry out any attacks in Yemen ," he said.