Media rights group Reporters Without Borders (RWB) has expressed concern about the fate of five Sri Lankan journalists detained by the police.
Security forces are accused of maltreating the journalists
The Paris-based group also called for an explanation as to why anti-terrorist police arrested them last week.
The journalists are being accused of receiving money from the Tamil Tiger rebel group, RWB says.
There has been no comment from the Sri Lankan government which has been fighting the rebels for decades.
RWB says that, after making inquiries, it has established that the journalists received money, but from a foundation in Germany for Tamil exiles.
The funds were aimed at financing a website and helping Tamil students, it says.
It also accuses the police of beating some of the journalists during the first days of their detention in order to extract confessions.
Among those arrested were V Jasikaran, the owner of a printing company and a writer known for his pro-Tamil views, RWB adds.
Also detained, on 7 March, was J S Tissanayagam, who writes for the Sunday Times, according to the group.
Campaigners for press freedom say Sri Lanka, which is caught in a bloody conflict between the government and Tamil Tiger rebels, is becoming one of the most dangerous places for journalists to operate in.
The situation for reporters is said to have deteriorated due to the worsening violence and unofficial censorship.
In a report last week, Human Rights Watch (HRW) accused the security forces and pro-government militias of being among the world's worst perpetrators of enforced disappearances.
The government accused HRW of exaggerating the extent of the problem.