A member of the armed forces walks at the scene of a grenade attack in Nairobi on April 29, 2012. A grenade set off by a gun-carrying worshipper in a Nairobi church killed one person on today and injured at least 10 others, police and witnesses in the Kenyan capital said. The attack targeted the God House of Miracle Church in Nairobi's Ngara neighbourhood, where residents said they tried in vain to detain the alleged assailant amid the chaos that followed the explosion. AFP PHOTO / STRINGER-/AFP/GettyImages (-/AFP/GETTY IMAGES)

A grenade attack on a Nairobi church Sunday killed at least one person and injured more than a dozen, the latest in a series of such attacks since Kenya sent troops to fight an al-Qaeda-linked militia in neighboring Somalia.

The attack unfolded during Sunday service at God’s House of Miracles International Church in Nairobi’s Ngara enclave, police officials said. It came days after the U.S. Embassy here issued a warning of an impending attack in the Kenyan capital.

“Timing of the attack is not known, however, the embassy has reason to believe that the potential attack is in the last stages of planning,” the embassy said in a statement.

Last month, grenades were hurled into a crowded Nairobi bus station killing nine and wounding 40. And days later in late March, a grenade detonated at a Christian gathering near the port city of Mombasa, killed one person. Minutes later, a second grenade attack unfolded at a bar near Mombasa’s main sports stadium.

There was no immediate claim of responsibility for Sunday’s attack. But in previous attacks local authorities have blamed Somalia’s Al Shabab militia, which is known to have recruits operating inside this East African nation. The militia has vowed to attack Kenya in retaliation for Kenyan forces entering their country.