Protests marked the celebration as militant groups were stopped by anti-riot police about a block from the heavily guarded embassy as they took turns in slamming Washington.
As scores of anti-riot policemen tried to keep the militant groups at bay, thousands of pro-US marchers cheered by waving "Happy Birthday, America" signs.
Police managed to separate both groups by some 200 meters as leftist protesters slammed Washington for its continued military intervention and "war of aggression" on Iraq.
Maita Santiago, Migrante secretary general, said over 250,000 Filipinos died in the Philippine-American War of 1899-1902, several Filipino workers have been killed in the Middle East since US President George W. Bush began the war in Iraq, and Filipino activists in the United States have allegedly been harassed by US authorities.
The militant Anakpawis said they would work for the cancellation of the RP-US Treaty of Non-Surrender which grants American troops immunity from prosecution under the International Criminal Court (ICC).
For its part, the militant women’s group Gabriela claimed the US government has a "warped sense of friendship" with the Filipinos.
"It is outright insulting to celebrate Fil-American Day, which historically is an affront to the Filipino people," Gabriela said in a statement.
Gabriela noted that "in the name of our friendship with women all over the world, we can only condemn the US’s continued military intervention and war of aggression."
Before the rally leaders spoke, other militants performed a skit with a man dressed as Uncle Sam beating a Filipino whose bare back was painted with the Philippine flag.
Some of the protesters carried a placard with Bush’s face and spray painted it with: "Meddlers are banned here" and "no welcome to Bush in October."
Wilson Fortaleza, of the group Sanlakas, said massive protests will greet Bush when he visits the Philippines in October.
In marked contrast, the presence of pro-US groups led by Discovery Crusade marched from CCP complex in Pasay City. The group did not escape the attention of anti-US protesters, triggering a heckling match.
Their marchers, however, plastered posters along Roxas Boulevard with anti-Chinese slogans "4 July 2003, Filipino’s independence day from Red Chinese oligarchy and slavery!"
Another pro-US group led by the United States Supporters’ Alliance, marched with a girl in the lead dressed to look like the Statue of Liberty, as mini-skirted majorettes twirled batons while swaying to the tune of "Dancing Queen" popularized by pop group Abba.