Kenyan police on Saturday said security forces have arrested four suspects in connection with the blast last week at Kenya's main airport. Police spokesperson Gatiria Mboroki told journalists in Nairobi that further investigations are ongoing so as to ensure the culprits are brought to book. "We are also asking Kenyans to remain vigilant as several attempted incidence of terrorist attacks have been noted in the past week," Mboroki said. She added that three persons suspected to be Al-Shabaab adherents were also arrested earlier this week while traveling from the northern part of the country to Nairobi. "The police is therefore on high alert and has intensified patrols and intelligence gathering in order to pre-empt further attacks," she said. The spokesperson said that members of the public should give information to the government if they sight anything suspicious. She added that over the last two weeks, police have been carrying out a disarmament exercise in Baragoi in the northern part of Kenya. "This exercise is progressing well and we have already recovered assorted illicit small arms and light weapons," he said. Mboroki said that the exercise will continue until peace returns to the region. "We would like to appeal to all communities living in the area to cooperate with the security forces carrying out the operation. Residents should volunteer to surrender illicit small arms and weapons in their possession," Mboroki said. The police also urged Kenyans to embrace the Nyumba Kumi initiative in order to address the immediate security concerns within our communities.