Tim Dahlstrom, deputy commander of the international police in East Timor, said his troops were working with local security forces in Dili to restore order.
"Twenty-five people were arrested ... for carrying weapons and rioting," he said, adding that guns, slingshots, spears and knives had been seized.
Gang warfare, looting and arson left 30 people dead and sent nearly 150,000 fleeing from their homes in May and June. The violence began after rival security forces fought on the streets of the capital.
A new government was put in place last month and the presence of foreign troops has largely eased tensions, but the weekend violence highlighted ongoing security concerns.
Mobs burned at least seven houses to the ground and threw stones and Molotov cocktails at a refugee camp near Dili's airport, terrifying residents but causing no injuries, officials said.
"It is important we get the community talking together to try to reconcile their differences," Dahlstrom said, explaining the need to work with local police.
"It is the community that must solve the problem."