NAIROBI (Reuters) - Two successive blasts in a residential area near the Kenyan capital's central business district wounded one police officer late on Friday but did not injure any civilians, police said.

A string of sometimes deadly attacks in Nairobi and the port city of Mombasa has been blamed on Somali militants and their sympathizers, retaliating for Kenya's decision to send troops into Somalia last October to drive out the militants.

The latest blast rocked the Somali-dominated area of Eastleigh, 100 m (yards) from a church on Nairobi's Juja Road where an explosion on Sept 30 killed a nine-year-old child attending Sunday school.

"We believe the first blast was intended to lure onlookers, members of the public, and that the second blast was meant to harm them," Kenya Police spokesman Eric Kiraithe told Reuters.

"One police officer was wounded, but his injuries are not life threatening," he added.

Kiraithe said the explosions had targeted a dumping site in a section of the sprawling working-class district.

The area was cordoned off and lit up with floodlights so bomb experts could scour it for shrapnel and any unexploded devices.

Kiraithe declined to say what may have caused the blasts, saying he could only comment after investigations were complete. He also declined to say who may have been behind the attack.

Local television stations said at least three police officers had been wounded in the blasts.

Kenyan troops have won control of the southern Somali port city of Kismayu, the al Shabaab militant group's last major bastion in the Horn of Africa country, as part of a year-long offensive to drive out the rebels.

Al Shabaab vowed to retaliate when Kenya sent troops into Somalia last October to crush the al Qaeda-linked group.

(Reporting by James Macharia; Editing by Michael Roddy)