Kenya has sent back 82 Somalis to Somalia after launching a massive security force operation to flush out illegal immigrants and militant Islamists.
The group had been in Kenya illegally, a Somali diplomat said.
Nearly 4,000 people across the country have been arrested in raids over the past week, and police say 447 of those are still in custody in the capital.
Somali militants have carried out a wave of attacks in Kenya since 2011.
The security operation has focused on Eastleigh, a mainly Somali neighbourhood in the capital, Nairobi.
At least six people were killed in grenade explosions in Eastleigh on 31 March.
No group said it carried out the attack.
However, Kenya's government believes that Somalia's militant Islamist group, al-Shabab, operates in Eastleigh, and has support among some Somalis living there.
Those arrested included women and children. They were taken to a sports stadium and various police stations to be interrogated and for their legal status to be checked, correspondents say.
"We have arrested almost 4,000 people in this operation," Kenya's Interior Minister Joseph Ole Lenku is quoted by Reuters news agency as saying.
Correspondents say the authorities did not make it clear how many of those are still in custody except for mentioning that 447 people were still being held in Nairobi.
"For the last few months we've had heightened insecurity. Time has come for a mop up to restore order," Mr Ole Lenku added.
The operation has been condemned by some leading Kenyan MPs and religious clerics who have accused the security forces of unfairly targeting Somalis.
Somalia's ambassador to Kenya, Mohamed Shake Ali, confirmed to the BBC that 82 people had been deported.
On Monday, the UN refugee agency, UNHCR, said it had been denied access to refugees and asylum-seekers who had been arrested.
Last month, Kenya's government ordered all Somali refugees living in towns to move into designated camps in a bid to end militant attacks.
On 24 March six people died in an attack on a church near the port of Mombasa.
In September, at least 67 people were killed after al-Shabab militants took control of the Westgate shopping mall in the capital Nairobi for four days.
Somalia has been been hit by instability for more than two decades, forcing hundreds of thousands of people to flee to Kenya.