NAIROBI (Reuters) - Eritrea should be punished for threatening the Horn of Africa region by supporting Somali rebels, Somalia's foreign affairs minister said on Sunday.

The United States, Britain, United Nations and the African Union (AU) accuse Eritrea of fanning the chaos in Somalia, through provision of arms and logistical support to the radical al Shabaab rebels, seen by Washington as al Qaeda's proxy.

"Enough is enough. Eritrea has defied calls from the international community and individual countries to play a positive role," Ali Jama Ahmed told Reuters.

Early this month, Britain told the U.N. Security council it was ready to punish Eritrea for its role in Somalia.The government in the Eritrean capital Asmara rejects accusations that it arms the al Shabaab insurgents.

Ahmed said that while the region had been trying to engage Eritrea constructively, its leadership had chosen to continue to be part of the Somalia problem.  He said Asmara had to re-engage with the region in its search for an end to the fighting and human suffering in his country.  "Eritrea has to take the right trail or face sanction which we hope the Security Council will impose soon," he said in the Kenyan capital on his way to Kampala for a meeting on Africa's 17 million refugees.

Somalis displaced from their homeland by the fighting account for a substantial proportion of those refugees.

MORE PEACEKEEPERS NEEDED

The minister said al Qaeda's presence in Somalia was not a secret and called for the AU to send additional troops.  "It is no longer in dispute that al Qaeda is active in Somalia and al Shabaab is promoting global jihad centres which is worrying Somali leadership and the region," he said.

"We need to focus on strengthening Somali security forces ... we hope AMISOM (AU peacekeepers) will be strengthened and the deployment of the original 8,000 troops will be completed soon.  " Only 5,000 Ugandan and Burundian peacekeepers have been deployed of the 8,000 promised by the AU.

Somalia's 18-years conflict has killed nearly 19,000 civilians since the start of 2007 and driven another 1.5 million from their homes.

Pledges by the international community to help the Transitional Federal Government, in its war against al Shabaab and Hizbul Islam rebels need to be fulfilled on time, he added. "We have to do everything in a concerted and comprehensive manner. The world has to come forward and play a more active role," Ahmed said.