The Islamic State militant group has claimed responsibility for the bombing attack in Uganda's capital city of Kampala, which had killed at least one person. The group released a statement to announce that it was responsible for the attack on Sunday, a day after the bombing.

In its statement, the group said the people that detonated the explosive device inside a restaurant were their members. The group said the bombing targeted "members and spies" of the "Crusader Ugandan government."

Just hours before the group claimed responsibility, President Yoweri Museveni said that he believed that the bombing was a terrorist attack. Museveni vowed to catch the perpetrators and bring them to justice.

The bomb exploded inside a restaurant in the outskirts of Uganda's capital. Police said that bomb was packed with nails and shrapnel, which were placed inside a polythene bag.

Investigators said three men had entered the establishment pretending to be customers. One of the men then placed the explosive device under one of the tables before leaving the restaurant. Moments later, an explosion occurred inside the restaurant, which killed a 20-year-old waitress. The restaurant, which is frequented mostly by commuters, was fortunately not as packed as in previous days.

Police said three other people were seriously injured by the blast. Two of the victims are reportedly still in critical condition. Before the Islamic State claimed responsibility, police already suspected that the incident may have been an act of domestic terror.

Police have already sealed off the scene and an investigation has already been launched. A bomb squad is reportedly already investigating the explosion to determine what type of device was used.

The incident has revived memories of a similar bombing in Kampala in 2010. The bombing, which had killed over 70 people, was carried by the Somali Islamic extremist group al-Shabab. The group claimed that the bombing was in retaliation against the Uganda government for its deployment of peacekeeping troops to Somalia.

Uganda is relatively peaceful and terrorist attacks are rare. However, several governments have already imposed travel advisories in recent months. The UK said in its travel advisory that terrorist attacks are likely and they could be indiscriminate.