In their place hang religious symbols -- a substitution that perfectly reflects the image Sri Lanka wants the world to see: Its former enemies on the path to redemption and rehabilitation.
More than 300 former members of the Liberation Tigers of Tamil Eelam (LTTE) -- including children forcibly recruited by the rebels -- are undergoing rehabilitation in tightly-guarded, state-run camps.
Where once they were trained for guerrilla warfare in the jungles of northeast Sri Lanka, they now receive vocational training in carpentry, masonry, plumbing, electrical wiring, sewing or cooking.
They are also learning computer skills, English and Sinhalese, the language spoken by Sri Lanka's ethnic majority.
It's a disconcerting regime for some of the former rebels, especially the younger ones who were raised on the struggle for an independent Tamil homeland, Tamil Eelam.
"I had read about Sri Lanka only in school books," said Vajeema Ravindran, 17, who now salutes the national flag and sings the national anthem every day.
"We only sang the Tamil Eelam song and saw the Tamil Eelam flag," Ravindran said.
The Welikanda centre, some 260 kilometres (162 miles) east of Colombo, throws up many contradictions.
In the evenings, it takes on the atmosphere of a community centre, as the former rebels spend their time listening to hip-hop Tamil or Hindi music, drawing or playing cricket or football.
There are movie nights with DVDs provided by relatives or old Tamil films aired on television.
But the external reality is of a compound guarded day and night by armed soldiers who decide who, if anyone, moves in or out.
"This is not a prisoner of war camp. It's more like a school," said Major Jayalal Suraweera, who runs the centre.
"This is a process of rehabilitation and not punishment," Suraweera told AFP. "Inmates can either return to their families or go abroad once their programme here ends."
Welikanda is home to around 150 former rebels, and the centre is being expanded to accommodate another 200.
More camps are expected to be built over the next few months with room for 3,000 fighters who surrendered during the final stages of the war.
According to Sri Lanka army chief General Sarath Fonseka, more than 9,000 Tiger rebels have been rounded up since the military's final victory over the LTTE in mid-May.
Some face criminal charges, while others will join the waiting list to be rehabilitated.
Thevanayagam Shankar, 29, a former Tiger eastern commander, gave himself up following the death of LTTE supremo Prabhakaran, who was shot dead by government troops as he sought to escape the Tigers' last holdout.
A 15-year veteran of the Tigers' struggle, Shankar is now spending a year in Welikanda.
"With Thalaivar (Prabhakaran) gone, there was no one to lead us," he said as he took a masonry class alongside some of the men he used to command.
Angelo Selvakumar, 35, who led several small LTTE fighting units for nearly a decade, is learning carpentry, and admits to finding tools harder to handle than guns.
"With a gun, people do things for you with fear. Money was easy. Now I have to learn how to earn money," Selvakumar said as he showed off his dormitory, where the walls are covered with pin-ups of Bollywood stars and cricketers.
--- Lost childhood ---
Another camp at Ambepussa, about 60 kilometres (38 miles) north of Colombo, is exclusively for former child rebels and houses more than 100 teenage Tamil girls and boys.
The UN Children's Fund has documented close to 7,000 cases of LTTE child conscription since 2006 -- although it believes that figure is a third of the actual number of children incorporated, often by force, into the rebel ranks.
"Kids are easier to train and can be easily brainwashed to commit crimes," says Hiranthi Wijemanne, a consultant with the justice ministry that runs the rehabilitation camps.
Puniyamurthy Mekaladevi had dreams of being a science teacher before she was snatched from her school by the LTTE. She served with the rebels for three years, before government troops overran her sentry post in January.
"I like it here. I get good meals, nice clothes. I want to study and be a teacher," Mekaladevi said.
According to Wijemanne, many of the children arrived at the Ambepussa facility in a poor condition after years of harsh living in makeshift jungle camps with little or no sanitation.
"Some of them were living like wild things. They came here with their hair matted with lice," Wijemanne said, adding that some had since succumbed to the vanity of normal teenagers with requests for skin lightening cream.
The camps have received a stamp of approval from the UN children's agency UNICEF which is involved in the running of the Welikanda facility.
"We have seen a positive experience in the children who are going through the programme," said the agency's chief of child protection in Colombo, Andy Brooks.
"The menu of options available to learn more skills is increasing as the programme matures.
"The programme is more relaxed and the government is doing a fairly good job to change these children from their military experience to a much healthier civilian experience," Brooks said.
For Colonel Modestus Fernando, the Deputy Commissioner General of Rehabilitation, the camps are key to the government's stated policy of ethnic reconciliation.
"It's our duty to protect them, to give these people a chance in life," Fernando said.
But life after rehabilitation will be fraught with its own difficulties.
For former Tiger commanders like Shankar, there is danger in the prospect of returning to communities where there is a legacy of deep bitterness over the LTTE's hardline policies towards fellow Tamils.
"Many people want us dead for our old life, families of people forced to fight, rival gangs. We can't stay here, we have to go abroad to stay alive," said Shankar.