Fears are growing for the safety of four British private contractors captured during a gun battle in the Horn of Africa.
Isaias Afewerki, the President of Eritrea, made a belligerent address on Saturday in which he condemned the group's possession of "countless numbers of arms" and refused to be drawn on their release.
The comments escalated a diplomatic rift that has been widening since Christmas Eve, when the four men were stopped near Eritrea as they travelled across the Indian Ocean. The confrontation resulted in a round of gunfire and saw the men arrested before being taken back to the mainland for incarceration.
British diplomatic sources say that numerous requests for access to the group have been turned down by authorities in Asmara, the capital. And this weekend, Mr Afewerki compounded fears after an address on state television in which he refused to say whether the group would be granted consular access. "They should ask what they were doing in our territory," he said. "They are citing the [Vienna] Convention when our laws were being violated."
He added: "They possessed countless amounts of arms, including sniper rifles. If you come into my house with a gun, don't I have the right to defend myself?"
The men, one of whom is Adrian Troy, 47, a British-born Western Australian, are contractors working for a Hertfordshire-based security company, Protection Vessels International (PVI).
Founded in 2008, PVI accounts for more than 40 per cent of all armed escort vessels operating in the Gulf of Aden, East Africa, and the Indian Ocean. Two of the men detained are former British military personnel.
Relatives of Mr Troy's are frustrated with the lack of progress from their British counterparts, and have lobbied the Australian government to accelerate discussions. Last week Mr Troy's regular employer, Steven Arrow of Arrow Pearls, said that his family and friends were "consumed with concern and worry".
Yesterday, a spokesman for PVI said: "In response to the recent comments by the Eritrean President, Protection Vessels International remains acutely concerned for the state of the four detained personnel ... still being held in Eritrea. It is working closely with the FCO to secure their release through diplomatic channels. Negotiations are ongoing and the issue continues to be sensitive for all concerned; however, we fully support the Eritrean government's ongoing investigation into this matter."
William Hague, the Foreign Secretary, has instructed the British embassy to raise the urgency of the issue "as a matter of priority", while diplomatic negotiations are being sought in New York, Brussels, Khartoum, Tripoli, Nairobi and Beijing.
Last month, the Conservative foreign minister Henry Bellingham warned Britain was ready to take "robust action" if Eritrea remained silent on the issue. Bellingham said consular access to check on the men's welfare should have been granted within 48 hours under the Vienna Convention on diplomatic relations, signed by both Britain and Eritrea.
Yesterday, a spokeswoman for the Foreign Office said: "We have been urgently seeking consular access since we became aware of their detention. We are deeply concerned at the failure of the Eritrean authorities to allow us to speak to or visit the men. The minister for Africa, our ambassador and other officials continue to demand access."