PHNOM PENH - Cambodian villagers threatened with eviction staged a rally Sunday with "SOS" banners urging US President Barack Obama to press the government on land rights during his upcoming visit.

About 100 protesters gathered at a well-known forced eviction site in the heart of the Cambodian capital carrying large black banners emblazoned with the word "SOS" next to photos of Obama and Secretary of State Hillary Clinton.

"We are asking Obama to save our lives," said Tep Vanny at the rally, held on a large plot of sand once home to her lakeside Boeung Kak community before a private company filled in the lake and displaced about 4,000 families. "We are demanding that Obama and Hillary help push the government of Cambodia to respect human rights, democracy and put an end to forced evictions and land disputes with villagers," she told AFP.

Tep, who is among a small number of residents still living on the site, has become a leading land rights activist in Phnom Penh. Obama will on Monday become the first sitting US president to visit Cambodia, where human rights groups accuse the government of stepping up a crackdown on dissidents and on protests, many linked to land disputes.

Clinton will accompany Obama on the trip.

The White House said Obama would raise "grave concerns" over the human rights situation in bilateral talks with Cambodian Prime Minster Hun Sen, who has kept a firm grip on power for 27 years.

The latest protest comes just days after eight residents facing eviction near Phnom Penh airport were briefly detained for painting "SOS" on their roofs next to portraits of Obama.

Rights groups say the government is working overtime to suppress criticism ahead of and during the high-profile East Asia Summit, which brings together leaders of 18 countries for talks on Monday and Tuesday.

Despite official warnings that no protests would be allowed during the meetings, Sunday's event went ahead without police interference and in view of the Peace Palace where Southeast Asian leaders were already holding talks.

National police spokesman Kirt Chantharith told AFP the authorities would only force the activists to disperse if they took to the streets.

"Actually they are wrong. But the government forgives them," he said.

"The government respects human rights but needs to keep public order for the summit."