Egyptian supporters from the ruling National Democratic party clash with a protester from the opposition Kifaya, or "Enough" movement, center
The White House says those who beat Egyptian opposition supporters should be brought to justice. The attacks came ahead of a referendum on key electoral reforms.

White House spokesman Scott McClellan says the Bush administration is very aware of reports that plainclothes Egyptian government agents beat protesters Wednesday then watched as supporters of President Hosni Mubarak punched other demonstrators.

Mr. McClellan says there is no excuse for attacks on peaceful demonstrators. He says freedom of assembly by opposition parties and critics of those in power is important when it comes to conducting free elections.

Mr. McClellan says it is the view of the White House that anyone who attacks peaceful demonstrators should be arrested and tried.

On the broader issue of Egypt's referendum on electoral reform, Mr. McClellan says President Bush welcomes President Mubarak's initiative to put in place a competitive presidential contest.

Mr. McClellan says that important step needs to be accompanied by international election monitors and a real campaign in which multiparty candidates are able to campaign freely.

Egyptian opposition groups called for a boycott of the referendum which requires presidential hopefuls to gain the support of at least 300 members of parliament. As that body is dominated by the ruling party, opposition leaders say the requirement means there will be no serious challengers to President Mubarak.

The Egyptian leader has not officially announced whether he will run for re-election in September, but he is widely expected to do so. President Mubarak has ruled the country since 1981, re-elected every six years without opposition in a simple yes, or no ballot.