Sri Lanka's defence secretary, Karunasena Hettiarachchi said the TID's arrest of former LTTE commanders is in relation to the reported finding of a suicide vest and unexploded explosives in Jaffna.

In an interview with the BBC, Mr Hettiarachchi said he could not make any comment until the investigation was over.

"After the investigations over and a reports are submitted only we can make a statement," he was quoted by Colombo Page as saying.

Denying there was any threat to national security, he added, "we currently do not have such a threat but if there is such a situation we will be vigilant."

US Ambassador Samantha Power heaped praise on Sri Lanka as a “as a global champion of human rights and democratic accountability,” in a speech delivered in Washington on Thursday.

Speaking at the signing of the United States-Sri Lanka Trade and Investment Framework Agreement Council, Ms Power said Sri Lankan President Maithripala Sirisena’s administration “has made extraordinary progress” towards seeking “a durable peace, an accountable democracy, a new relationship with the outside world, and expanded opportunities for all”.

The ambassador also reiterated the “importance President Obama, himself, places on the United States’ bilateral relationship with Sri Lanka”.

“More specifically, our commitment – and his commitment – to Sri Lanka’s continued progress, and our determination to support President Sirisena in his efforts to ensure that this progress delivers socio-economic benefits for the people of Sri Lanka,” she added.

“Sri Lanka has, since January 2015, emerged as a global champion of human rights and democratic accountability,” the ambassador stated.

Updated 2100 GMT

Sweden’s Foreign Minister Margot Wallström arrived in Jaffna on Tuesday, ahead of a series of meetings with civil society activists, displaced Tamils and the Chief Minister of the Northern Province.

On arriving in the North-East, Ms Wallström was greeted by Jaffna’s Government Agent Mr N Vethanayaha, as she held a meeting at the District Secratariat.

Another two Tamils in the North-East were abducted in a white van on Tuesday.

George Rajanayakam, 42, and V Michael, 45 were taken near Kattaikadu, Mulliyan, as they were about to go out to sea to fish, when the men came in a "Dolphin" van.

"Both of them are family man, and we are not aware of the reasons behind their abduction. They never had any connections with the LTTE" relatives of the men said.

Tensions in the Vadamaradchi area remained high on Wednesday according to local residents due to the spate of abductions and arrests by the TID. Former LTTE cadres are reported to be moving away from their homes. Sri Lanka's ministry for rehabilitation has further summoned former members of the LTTE to Colombo on April 30th, without giving them a precise location.

UK-based Freedom from Torture has hailed the forthcoming "historic visit" of the UN Special Rapporteurs on Torture and Independence of Judges and Lawyers to Sri Lanka.

In a statement, International Advocate and Researcher Ann Hannah said the officials " have a crucial role to play in holding the government to its international commitments".

"This must include meaningful survivor consultation on an internationalised justice process as well as other measures in order to build trust across communities and deliver long-term peace and reconciliation," she said, pointing out that torture was still ongoing.

“However, we cannot ignore that this visit takes place against a backdrop of ongoing torture. Freedom from Torture has received 248 cases of torture since 2009 including 17 referrals for torture in 2015 under the current government. This undermines the government’s work to secure a stable and prosperous Sri Lanka,

The US and Sri Lanka will adopt an ambitious joint action plan to promote greater trade and investment and major reforms in Sri Lanka in Washington DC later today.

In a media brief the US government said,

The Chief Minister of the Northern Province C V Wigneswaran discussed Tamil calls for federalism with Sweden’s Foreign Minister Margot Wallström, as she toured Jaffna on Tuesday.

Justice Wigneswaran outlined Tamil demands for a political solution that allows the Tamil people to govern themselves through a federal system.