* Authorities say gunmen escaped
* Kenya worried by radicalisation of Muslim youths
* Somalia's al Shabaab blamed for similar attacks (Updates toll, adds second witness, minister)
By Joseph Akwiri
MOMBASA, Kenya, March 23 (Reuters) - Two gunmen stormed a church near the Kenyan coastal city of Mombasa on Sunday and opened fire on worshippers, killing four people and wounding others, in what police called a terrorist attack.
One witness said the gunmen shouted out in a foreign language before shooting indiscriminately at the congregation. Blood-spattered Bibles and overturned plastic chairs lay strewn across the church's floor after the attack.
"Both carried big guns and began shooting all over the place. I fell to the ground and could hear screams," said Lilian Omondi, who was leading a prayer recital at the time.
Another bystander said the assailants walked unhurriedly out of the church and opened fire on people standing outside. An Interior Ministry official later said they escaped.
"They were ordinary looking guys, one of them tall, dark and wearing a long-sleeved shirt. They walked casually as if all was ok," said Peter Muasya. "Then they started shooting at those of us who were standing outside."
Somali militant group al Shabaab and local sympathisers have carried out multiple attacks in Kenya, in revenge for the Kenyan army's intervention in Somalia to crush the Islamist rebels.
Along Kenya's Indian Ocean coast, tension is high particularly among Muslim youths who claim the security forces have been heavy handed in their crackdown on militant recruitment.
Kenya's parliament has called for better coordination between the security and intelligence agencies after 67 people were killed in a shopping mall attack in Nairobi in September.
The church shooting took place in Likoni, located across a deep-water channel from Mombasa city, a major tourist hub. It came days after prosecutors charged two Somalis with terrorism offences after police seized a car packed with explosives.
There was no immediate claim of responsibility. Likoni's police chief Robert Mureithi said it appeared the gunmen were armed with automatic weapons.
The attackers tried to raid a second church nearby but fled when armed police on patrol in the area appeared.
"This has all the indicators of a terrorist attack because the attackers did not steal anything and appeared focused on killing," Mureithi told reporters at the scene.
Two people were killed at the church and two people died of gunshot wounds in hospital, according to the Kenyan Red Cross.
At Mombasa's main hospital doctors handed reporters x-rays showing bullets lodged in the skulls of a two-year-old boy, whose mother was killed, and a male adult they were treating.
Kenyan security officials say the Indian Ocean coastline has become a hotbed of radicalisation.
"Terrorism continues to grow in shape, colour and behaviour and when it assumes the phase of radicalisation ... it will be met (with) full force," Interior Minister Joseph Ole Lenku said in Mombasa on Saturday.
Moderate clerics in Mombasa warn the forceful the crackdown on militant recruitment networks is fuelling resentment.
Kenyans are increasingly alarmed at the relative ease at which militants appear to move within the country, east Africa's biggest economy and a recipient of U.S. counter-terrorism funding.
Al Shabaab said it carried out the Westgate mall siege in the capital to avenge the military deployment in Somalia and has threatened more strikes in Kenya and other nations which have sent troops to Somalia, including Uganda and Ethiopia. (Writing by Richard Lough; Editing by Rosalind Russell)