Mogadishu - Somalia's Islamic extremist rebels, al-Shabaab, are making a comeback, having recently seized four towns and attacked a guesthouse in neighboring Kenya, killing 12.The resurgence of al-Shabab, which is allied to al-Qaeda, could affect Somalia's plans to hold elections next month and further destabilize what is already one of the world's most failed states.The rebels had steadily lost ground over the past five years, first losing control of the capital, Mogadishu, in 2011 and then being pushed out of virtually all of Somalia's other major cities and towns. This was largely the work of the African Union force of 22 000 soldiers from Ethiopia, Kenya, Uganda, Burundi and Djibouti, which is supported by the UN. The relatively weak Somalia army, with 35,000 troops, also participated in the operations.Al-Shabab was reduced to roaming around Somalia's vast, arid scrubland, and staging deadly suicide bombing attacks in Mogadishu and other centers. In recent months there have been increases in attacks on hotels and also al-Shabab has directly attacked African Union bases.But now this month Ethiopia — which has 2 000 troops in the African Union force and an unknown number operating independently in Somalia — pulled its forces out of the towns of Halgan, El-Ali and Mahas in the Hiran region of south-central Somalia. Al-Shabaab wasted no time and within hours its fighters had seized control of those towns where they raised their black flags.Anti-government protests On Wednesday, Ethiopian troops withdrew from a fourth town, Tiyeglow, in the southwestern Bakool region, and al-Shabaab retook it.Al-Shabab's swift seizures of the newly exposed towns are worrying for Somalia, facing a presidential election in late November.It is not known how many Ethiopian troops have been pulled out of Somalia, but analysts say they were withdrawn in response to Ethiopia's need for troops at home to enforce the state of emergency imposed to quell months of anti-government protests."Returning a large number of troops back home left the Ethiopian army overextended in Somalia, so abandoning some ground in Somalia is inevitable," said Mohamed Sheikh Abdi, a Somali political analyst.Meanwhile, Somalia's civilians are bearing the brunt of the withdrawals, with militants executing suspected government collaborators in each location they recapture, say residents."They left without informing us, only to find al-Shabab here and killing our elders," a resident told The Associated Press by telephone, on condition of anonymity for security reasons. "We would rather have al-Shabab here than having unpredictable soldiers leaving us in the open."Ethiopia's government spokesperson, Getachew Reda, said Ethiopia's recent pullout from certain places in Somalia did not include relocating the country's forces that are part of the multinational African Union mission.Pressing troubles "But the troops that we sent to Somalia on our own do not necessarily have to stay there as long as (the African Union mission) does," Getachew said Wednesday.He said the troop pullout is not related to his country's six-month state of emergency, which was declared on October 8, and he said the troops that were moved from Halgan were transferred to other bases in Somalia.But he urged the international community to step up and "take up the slack from us" in Somalia, saying that "for our forces to remain there indefinitely would be the height of irresponsibility".Somalia and African Union officials were not available for comment on this month's withdrawals."Ethiopia has more pressing troubles on its hands now, so it cannot focus on outside missions much. The focus should be to avoid the Arab Spring-style violence" at home, said Ahmed Mohamed, a retired Somali military colonel in Mogadishu.Somalia's security forces are supposed to be taking on more responsibility as the African Union force prepares to withdraw by the end of 2020, but this month's attacks indicate that the Somali forces may not be able to hold the gains made by the African Union troops that deprived al-Shabaab of large parts of territory.This week al-Shabaab also attacked a guesthouse in Kenya in which it killed 12 non-Muslims in Mandera County, near the border with Somalia.Al-Shabab's resurgence comes after the extremist group recently splintered, with some former members forming an offshoot that is allied to the Islamic State group, instead of al-Qaeda. The fighters allied to ISIS this week claimed control of a town in the north, in the semi-autonomous Puntland region, but then withdrew on Wednesday night, according to residents.