The coordinated rebel attacks on East Timor's president and prime minister are a further tragedy for a young country still trying to find its feet after final independence in 1999. The shooting of President Jose Ramos-Horta is the more shocking because, in 1996, he won the Nobel Peace Prize for the statesmanlike way in which he helped lead his country away from outside rule.

Yesterday's attacks are also a setback for the international community which, having pressured Jakarta into withdrawing, ploughed considerable resources into the new country. The UN Mission of Support in East Timor was wound up in 2005 having, as it thought, established sound economic, institutional and political foundations. At the time the mission was hailed a success, but very quickly instability broke out as rival gangs fought each other. Less than 12 months later, UN peacekeepers were back, 1,500 UN police backed up by a thousand Australian troops. It was only at the beginning of this month that the UN once again announced that it would start returning security control to East Timor's police.

There is a range of surface sources for the violence, including the anger of the opposition Fretilin party at the president's choice of independence hero Xanana Gusmao as prime minister, as a way of breaking political deadlock caused by inconclusive elections.

Gusmao managed to form a coalition in 2007, excluding Fretilin There are also complaints from citizens from the west of the country who feel that they are excluded from the better opportunities in society. It was "westerners" among East Timor's army who went on strike and were fired in 2006 - fully a third of the force. And it was from these ex-soldiers that came the rebel forces, largely led by Alfredo Renaldo, who have been responsible for much of the subsequent violence. It may possibly have an effect on the crisis that Renaldo was himself killed in the attack on the president. But probably not.

Unfortunately, there is a deeper cause of this unrest. Money. East Timor, currently one of Asia's poorest nations, is set to enjoy wealth from its substantial offshore holdings of oil and gas, which will be exploited jointly with the Australians. The final delineation of East Timor's border with Indonesia will have some impact on precisely how much oil and gas the country will have. Encouraged by the UN, the Australians have promised maximum employment opportunities for East Timorese and also claim they will help the government in the capital Dili, not only spend the oil income wisely but also invest part of it for the long term. The Indonesians, however, cannot fail also to be interested in the country's oil wealth. Why should it not be extracted via Indonesia's existing infrastructure? And there are probably other, less obvious, international players with their own ideas for East Timor's future.

So yet again, a sovereign country is being destabilized by outsiders and the price is being paid in the blood of its citizens.