More than 10,000 security forces have been assigned to keep order during the summit as part of Hun Sen's determined effort to show Cambodia's best face to the outside world.
National police spokesman Kirt Chantharith confirmed that eight people — six women and two men — were arrested at the village. He declined to say what charges they face.
Human rights groups have urged Obama to demand that Hun Sen address human rights abuses and implement genuine reforms. Obama will also visit Thailand and Myanmar on his first overseas trip since winning re-election.