Ethiopia's PM Meles Zenawi says Ethiopian troops can be pulled out of Somalia "within a few weeks", adding that the victors of Somalia's two-week war are now "mopping up remnants" of the country's former Islamist leaders. Addis Ababa, which backs Somalia's weak transitional government, launched

an offensive on Dec 24 against the Islamist movement which has controlled much of the country's south since June. After Ethiopia sent in thousands of troops, supported by tanks and fighter jets, the Islamists retreated rapidly and on Jan 1 fled Kismayo port, their last stronghold. But despite promises of a swift withdrawal, doubts remain about when Meles would be willing or able to pull back his troops. Ethiopia is believed to have had troops in Somalia for months before it announced its military presence in December and the Somali PM Ali Muhammad Gedi, said the forces should stay for months until the country had been pacified. Ethiopia faces a painful dilemma: if it withdraws too quickly it could leave a security vacuum in an often threatening neighbour that has endured 15 years of chaos and violence. However, the longer the troops stay, the more likely the Ethiopians could be seen as an occupation force or become embroiled in a guerrilla war with the remaining Islamist forces. Some observers said that while Addis Ababa had legitimate security concerns, it had broken international protocols by invading Somalia. But Washington, which also accused the Islamist movement of including al-Qaeda suspects, is believed to have given tacit support to Ethiopia to mount its offensive. The military operation will also be a drain on Ethiopia's meagre resources. The country maintains one of Africa's largest armies, estimated by an Ethiopian analyst to be about 150,000 troops, down from a figure of up to 300,000 during its 1998-2000 border war with Eritrea. But the impoverished country of 77m people is dependent on donor funding and Meles' government has agreed to keep military spending at a flat cash rate of 3bn birr ($355m, 269m, [pounds sterling]181m) a year in recent years. Aid donors will be monitoring to see if there has been any rise in defence spending. "We will be looking very carefully to see if Somalia has had an impact", said one western diplomat in Addis Ababa. "If it has, we will take a very serious view of that". Regardless of the aid advantages of a swift withdrawal from Somalia, it is likely to take weeks before a peacekeeping mission could deploy and fill any security vacuum. Diplomats and the Somali government have called for an African-led operation, but it is unclear who would finance or contribute troops to the mission. An official with the cash-strapped African Union, which is already overstretched providing peacekeeping troops in Sudan's Darfur region, told the FT the organisation was still internally discussing proposals.