THE United Nations’ top human rights official has warned that Syria could descend into civil war unless the international community supports a peace plan and an investigation into the killing of more than 100 civilians in Houla last week.Navi Pillay said on Friday that Syria and the entire region were in danger if a full-fledged conflict erupted in the country, as government forces opened fire on protesters in the Douma area near the capital Damascus, activists said. UN monitors reported that at least 13 people were killed in violence during protests that broke out in towns and cities across Syria to condemn the May 25 killings.The UN’s Human Rights Council is meeting in Geneva, Switzerland, to discuss the massacre in Houla, a cluster of villages in the centre of the country, that left 108 people dead, many of them children.The incident was one of the deadliest incidents since the uprising against President Bashar al-Assad’s regime started in March last year, and has drawn global condemnation.Countries including the US, Britain, Australia, and France expelled Syrian diplomats in protest.Pillay urged an investigation into the Houla massacre, after the council put initial blame on government bombardment and gunmen loyal to Assad."Otherwise, the situation in Syria might descend into a full-fledged conflict and the future of the country, as well as the region as a whole could be in grave danger,” she said in a statement read to the council.Annan frustrationPillay urged world leaders to support the six-point peace plan negotiated by UN-Arab League envoy Kofi Annan, which calls on both the opposition and government forces to cease hostilities.Annan on Friday said he is frustrated at the situation in the Security Council and repeated his calls for a unified approach, adding that it is up to the council to decide what new measures could be used to put an end to the violence."This is a decision that the Security Council will have to take ... What is important is that we continue our efforts to find a solution that leads to a transition in Syria,” Annan told journalists after talks in Beirut with Najib Mikati, Lebanon’s prime minister."A democratic transition that fulfills the aspirations of the Syrian people.” A draft resolution, circulated within the Human Rights Council late on Thursday, condemns the "killings confirmed by UN observers” in attacks that involved "the wanton killings of civilians by shooting at close range and by severe physical abuse by pro-regime elements and a series of government artillery and tank shellings of a residential neighbourhood”.