Kenya has condemned a US decision to issue a travel advisory in the wake of this week’s blatant attack on a shopping mall in Nairobi that killed scores of people.

Kenya's Ministry of Foreign Affairs said in a statement issued on Saturday that the announcement was unnecessary and uncalled for.

"Terrorism, such as the attack on the Westgate mall, is a global problem. The United States itself has suffered terror attacks before, and so have other countries across the globe," said the statement.

It called on Washington to withdraw the advisory, saying the government will pursue the matter through diplomatic channels.

The US State Department issued the updated advisory on Friday following the September 21 attack on the Westgate mall.

Five Americans were also injured in the deadly assault. The advisory warns US nationals to take caution in light of ongoing terrorist threats.

Washington says it continues to receive information about "potential terrorist threats aimed at US, Western, and Kenyan interests in Kenya, including in the Nairobi area and in the coastal city of Mombasa."

According to reports, the dead in the mall attack also included three British nationals, two French women, two Canadian citizens, one of them a diplomat, a Chinese woman, two Indians, a Ghanaian poet, a South Korean, a South African, and a Dutch woman.

Somalia’s al-Shabab militants have claimed responsibility for the assault and warned the Kenyan government to withdraw its troops from their country.

Late on Wednesday night, al Shabab ringleader Ahmed Godane confirmed that the group was behind the attack on the mall, saying the raid was in retaliation for the Kenyan military’s invasion of southern Somalia in October 2011.

"Take your troops out or prepare for a long-lasting war, blood, destruction and evacuation," Godane said in an audio message posted on an al Shabab-linked website.

Kenya has more than 4,000 army soldiers in southern Somalia, where they have been battling the al-Shabab fighters since 2011.

The Kenyan troops are part of the African Union Mission in Somalia (AMISOM) that gets training and equipment from the United States.

Somalia has not had an effective central government since 1991, when warlords overthrew former dictator Mohamed Siad Barre.