LONDON (Reuters) - Under pressure in his Pakistan enclaves, Osama bin Laden is facing a familiar quandary: Where to go next? The answer is unlikely to be Yemen or Somalia, despite their new prominence as regional Al Qaeda sanctuaries. US drone attacks and a looming Pakistan Army offensive against one of Al-Qaedas main allies in a northwestern tribal area have stirred speculation that Osamas men are seeking a less risky refuge for their anti-Western campaign. But simply leaving Pakistans remote Federally-Administered Tribal Areas (Fata) could expose the worlds most wanted man and his entourage of planners and bodyguards to satellite detection and the curious gaze of a local population of uncertain loyalty. The moment that Al-Qaeda has to leave the Fata, that is the end of Al-Qaeda as an organisation, said Thomas Hegghammer, a research fellow at Harvard University. Yemen was a pretty good safe haven for lower-level members of Al-Qaeda provided the group did not get too strong and did not bring in the leadership. The presence of senior figures would provoke a tough security response from the government and the US, he said. Its conceivable Al-Qaeda could move. But it would be hard to find safe haven in another state, said David Claridge, managing director of Janusian Security Risk Management. Raphael Perl, an official of the Organisation for Security and Cooperation in Europe (OSCE), said moving out of Fata would put Al-Qaeda at risk because militants were at their most vulnerable when in transit from one safe haven to another. Its like a fish out of water, he said. At first sight Yemen and Somalia, as well as parts of central Asia and Afghanistan, might look suitable new havens. Yemen is Osamas ancestral home and Yemenis figure prominently in Al-Qaeda ranks. Osama once praised Muslim lions in Somalia for being able to grind Americas pride into dust in a 1993 clash with US forces. And moving camp would be nothing new for Osama, his number two Ayman al-Zawahri or other senior associates. US officials have told journalists that some Al-Qaeda fighters have begun moving to Yemen, a neighbour of oil giant Saudi Arabia, and Somalia because Pakistan had become too risky. But Gregory Johnsen, a Yemen specialist at Princeton University, said he doubted there was firm evidence showing recent militant arrivals in Yemen were from Pakistan. For Al-Qaeda, Fata still has attractions, despite mounting risks. Its members have lived there for years, weapons are plentiful and few of Pakistans federal laws apply. Perl of OSCE said he expected Al-Qaeda would adapt to the pressure in Pakistan as it had adapted to earlier challenges. The challenge (for the West) is to stay ahead of them in the adaptation process - two moves ahead, not just one.