Kenya is to build a 440-mile wall along its border with Somalia in a bid to keep out militants from al-Shabaab in a bid to boost security after a wave of attacks that have claimed scores of lives and brought severe criticism of the government’s response, The Telegraph reported.

The wall, a series of concrete barriers, fences, ditches and observation posts overlooked by CCTV stations that is expected to stretch from the Indian Ocean to the city of Mandera where both countries converge with Ethiopia.

Construction is said to have begun last week at Kiunga in Lamu county, where al-Shabaab militants are believed to hide out along with smugglers in uninhabited islands off the Indian Ocean coast.

"We expect to have finished the project before the end of the year,” Issa Timamy, the Lamu county governor, told Kenya’s Daily Nation recently.

"This is where immigrants have been arrested trying to cross into the country or having already entered through the border in Lamu [an island off the Kenyan coast.

“This is a good idea and we support it because we believe it will go a long way to secure this region and indeed, the country as a whole.”

It is part of a series of measures announced by the Kenyan government to crack down on extremism in its midst in the wake of an attack by al-Shabaab on Garissa University in the northeast which saw 148 people, most of them students, killed.

Money transfer agencies that operate between Somalia and Kenya have also been closed, along with civil society organisations working with Somalis.

William Ruto, the Kenyan deputy president, set a deadline of three months for the United Nations to close the Dadaab refugee camp, which is near the border with Somalia and the largest of its kind in Africa, and relocate more than 500,000 Somalis.

"The way America changed after 9/11 is the way Kenya will change after Garissa," Ruto said.

Critics of the crackdown have point to suggestions however that all four of the Garissa attackers came from Kenya, rather than over the border.