Six people have been killed in explosions in the Kenyan capital, Nairobi, officials say.
Several people were wounded in the attack, which took place in the Eastleigh suburb of the city.
More than 200 people were arrested in Eastleigh following the explosions, a police spokeswoman said.
Eastleigh is known as "Little Mogadishu" because of its large Somali population.
Although no group said it was behind the latest attack, many are blaming it on the Somali militant group al-Shabab.
Four members of the group were behind the four-day siege at a shopping centre in Nairobi last September, in which 67 people died.
Eyewitnesses said devices appeared to have been thrown towards a bus stop and a food kiosk as people made their way home for the evening.
Kenya's Standard newspaper said that the twin blasts went off some 50m (165ft) apart on 11th Street, and some of those caught up in the attack had serious injuries.
"We suspect it is a grenade," a local police officer told the AFP news agency.
Eastleigh has seen several recent grenade attacks, including one in December last year that killed four people.
The BBC's Caroline Karobia in the capital, Nairobi, says the 200 arrests do not come as a surprise - the police tend to carry out mass arrests after such attacks and charge people with petty offences like loitering, she says.
A week ago, more than 100 people were arrested following an attack on a church near the coastal city of Mombasa.
Unidentified gunmen entered the church, killing six people.
Kenya's government has ordered all Somali refugees living in towns to move into designated camps in a bid to end the attacks.
Interior Minister Joseph Ole Lenku said the directive had been issued because of the "emergency security challenges" facing Kenya. A refugee group condemned the decision as illegal.
Kenya has several thousand troops in Somalia, helping the UN-backed government tackle al-Shabab, who are linked to al-Qaeda.
President Uhuru Kenyatta has said Kenya's tourism sector is "on its knees" because of the threat from Islamist militants.
Mr Kenyatta met ethnic Somali leaders last week to ask for their help in identifying people they thought may be behind recent attacks in the capital.
"We all have a responsibility to bring this to an end," Mr Kenyatta said.