Bus blasts kill at least three in Nairobi

At least three people were killed and 62 others wounded when two homemade bombs exploded on buses along one of the busiest highways in Nairobi on Sunday, Kenyan authorities said. The attacks come a day after two blasts at the Kenyan coast killed four people.

Of the 62 wounded, 20 were in critical condition, according to the National Disaster Operations Center. Kenyan newspaper The Daily Nation said five children are among the critically injured.

Sunday's blasts happened on two buses packed with commuters along Thika Highway, said Moses Ombati, the deputy police chief in Nairobi. Eliud Lagat, the deputy head of the bomb disposal unit said the blasts were caused by improvised explosive devices.

The Daily Nation said the 45-seater buses were almost full when the blasts occurred.

Kenya has been hit by a wave of gun and explosives attacks since it sent troops to neighboring Somalia to fight Al-Shabab in 2011. The Al-Qaeda-linked group has vowed to carry out attacks in Kenya in revenge for deploying Kenyan troops to Somalia.

Public warnings of attacks have been near constant in Kenya in recent months, particularly after the attack on Westgate Mall left at least 67 people dead in September. Al-Shabab claimed responsibility for that attack.

Last month, a car bomb exploded outside a police station in Nairobi, killing two officers and two men of Somali origin inside the vehicle. Police had impounded the car for driving on the wrong side of the road. Three ethnic Somalis have been arrested for the blast and are expected to be charged in court this week.

Since last month, Kenya has been conducting a security operation in response to the attacks. Thousands of people, mainly ethnic Somalis, have been arrested in the security sweep which has been heavily criticized by human rights groups who say officials have indiscriminately imprisoned and subsequently abused Somalis.

Rights organizations accuse the police of detaining suspects without trial, denying them representation, circumventing the courts to deport Somalis back to Somalia and holding the suspects in inhumane conditions, as well as practicing extortion.

Al Jazeera and wire services