Indonesia's police chief said Friday he could not rule out a potential security risk for US President Barack Obama's planned visit this month, as more suspected militant violence hit the province of Aceh. Police killed two suspected militants and detained eight others in a shootout in Aceh on Sumatra island, just three days after police shot dead Dulmatin, a top fugitive militant wanted over the 2002 Bali bombings, near Jakarta. Asked whether there could be any link between the suspected militants and Obama's March 20 visit, National Police Chief Bambang Hendarso Danuri said: “The vulnerability is there.” He did not elaborate, but said the army would handle the escort for the Obama trip and the police would be a second tier. The head of the nation's anti-terrorism unit told Reuters last month police have stepped up monitoring of Islamist networks, but had found no indication of any plots targeting the US president's March 20-22 visit to Indonesia. Obama is popular in Indonesia after spending fours years in the country as a child, although US foreign policy in the Middle East sometimes provokes anger in the predominantly Muslim nation. Police have launched a series of raids across the archipelago following the discovery of a suspected militant training camp in a jungle area of Aceh Besar district last month. Police in Aceh have been hunting for about 30 other militants believed to be on the run. Friday's shootout took place in Leupung, about 24 km (15 miles) from the provincial capital Banda Aceh, after local police searched a mini bus. Two suspected militants were killed and eight others were detained, witnesses and local police said. Several M-16s and AK-47s, as well as a pistol, were confiscated. “I was eating when I suddenly heard incessant gunfire from outside. I jumped to the ground and lay low,” said a woman, who declined to be named. Danuri confirmed that two men were killed and eight detained in Aceh. “There was enforcement action against a terrorist group, the same terrorist group we had raided in Aceh Besar,” he added. Dulmatin, a leading figure in Jemaah Islamiah, had fled to the southern Philippines in 2003.