Five years after al-Shabaab fighters burst into a luxury shopping mall in Kenya's capital, hurling grenades and starting a days-long siege that left 67 people dead, analysts say the Somalia-based extremist group has been pushed down Africa's east coast as far as Mozambique as its regional threat expands.The assault on Westgate Mall on a sunny weekend afternoon horrified the world and exposed weaknesses in Kenya's security forces after it took them hours to respond. Kenyan President Uhuru Kenyatta promised reforms.Now the government of east Africa's commercial hub is praising itself, saying security forces have effectively limited attacks to areas near the Somali border. "We learnt our mistakes and corrected them," police Inspector General Joseph Boinnet told reporters this week, pointing out real-time intelligence sharing among security agencies.Analysts, however, say few sustainable lessons have been learned while al-Shabaab, the deadliest Islamic extremist group in sub-Saharan Africa, has changed its strategy with devastating effects.The al-Qaeda-linked extremist group has vowed retribution on Kenya for sending troops to Somalia since 2011. The group has killed hundreds of people inside Kenya, which has been targeted more than any other of the six countries providing troops to an African Union force in Somalia.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook"Al-Shabaab's goal in carrying out attacks outside Somalia is to pressure authorities within the region to pull their troops out of Somalia. That aim has not been achieved and all indications are that the movement continues to plot assaults in cities across East Africa to advance its objectives," said Murithi Mutiga, a senior analyst with the International Crisis Group.A new report by the think tank says some al-Shabaab extremists previously based on the Kenyan coast have moved south into Tanzania and, in response to crackdowns there, relocated into northern Mozambique and forged ties with local fighters.The Kenyan government's initial response to the Westgate attack, involving blanket arrests of Muslims and indiscriminate crackdowns aimed at ethnic Somalis, inflamed communities and made matters worse, Mutiga said.The government later changed its approach and appointed local ethnic Somalis to lead security operations in the northeast near the Somali border.That area, however, has seen growing attacks by al-Shabaab that have killed more than 100 police officers since May 2017."Kenyan security officials seem to have failed to contain that threat," Mutiga said. Other major attacks since Westgate in the region, often targeting Christians, have included massacres of bus passengers and the assault on Garissa University in 2015 that left 147 people dead.The pressure on al-Shabaab since Westgate has included training and counterterrorism equipment provided by Western countries including the US and Britain.'All life is precious and must be protected'The attack also changed the way Kenyan institutions are protected. Shopping malls, office buildings, university campuses, government facilities and the main airport have invested substantial sums in additional security, including surveillance.As al-Shabaab focuses its attacks largely on Christians in Kenya's Muslim-majority border communities, it has managed to stall economic activity and education, said Kenya-based security analyst and former US Marine Andrew Franklin. Many children who drop out of school as teaching staff flee become targets for recruitment by the extremists.Kenyans make up the majority of al-Shabaab's foreign fighters.While economic activity in the borderlands weakens and corruption grows, the morale and effectiveness of security forces has eroded, Franklin said.There is a "tremendous amount of complacency" among security agencies, he said, leading to the conclusion that senior officials have little interest in countering al-Shabaab's insurgency.For Andrew Munya, who was injured in the Westgate attack when shrapnel hit his left shoulder, Kenya will not be safe until al-Shabaab is dealt with for good."There is no difference whether a life is lost in the border areas or in the city," said Munya, who later became a security consultant while vowing to never to let his community and family become victims. "All life is precious and must be protected."