URIBE, Colombia (CNN) -- Millions of Colombians marched in anti-war
                  protests Sunday as formal negotiations aimed at ending Colombia's nearly
                  four-decade civil war resumed.

                  As many as 6 million Colombians marched in 15 cities across the
                  country as representatives of the government and the Revolutionary Armed
                  Forces of Colombia met in the village of Uribe after months of delays.

                  Waving flags and green peace ribbons, the protestors united under the
                  simple slogan, "No Mas" -- no more violence, no more kidnapping, no more
                  conflict. Demonstrators called for a cease-fire, a rapid settlement of the
                  conflict and an end to violence against civilians -- the conflict's principal
                  victims.

                  Both leftist rebels and right-wing militias regularly target non-combatants
                  they accuse of helping their enemies. Organizers of Sunday's marches said
                  they hoped they would establish a trend in a country where years of violence
                  have bred indifference and apathy.

                  The conflict began four decades ago and has escalated steadily since the
                  mid-1960s. About 20,000 leftist rebels are now battling the government,
                  calling for an end to poverty and political corruption.

                  Hopes for peace surged last year when President Andres Pastrana met with
                  rebel leaders in their jungle headquarters. Since then, that optimism has
                  waned as the the two sides failed to agree on ground rules for negotiation.

                  The conflict is worsening as Colombia's economy remains mired in its deepest
                  recession since the 1930s. Thousands of upper- and middle-class Colombians
                  are fleeing abroad. Colombian exiles in Los Angeles; New York; London; Caracas,
                  Venezuela; and Saudi Arabia joined in with their own demonstrations.

                  In Uribe, a southern rebel-controlled town where negotiations with the leftist
                  Revolutionary Armed Forces of Colombia, or FARC, were formally inaugurated
                  on Sunday after months of delays, rebel commanders put their own spin on the "No
                  More" message. On dusty streets, guerrilla banners demanded: "No More
                  Unemployment," "No More Massacres," "No More Torture."

                  Some townspeople wore shirts with the message "No More Gringo
                  Military," a reference to the stepped-up U.S. military aid being used by
                  Colombia's government to fight guerrilla units that protect the illegal drug
                  trade.

                      Reporter Martin Hodgson and The Associated Press contributed to this report.