Prisa's radio division Union Radio, Spain's biggest media group, enabled millions of Latin Americans to listen in on the "Peace Without Frontiers" concert, played Sunday midday local time on the Colombia-Venezuela border.

The concert was the idea of Colombia peace-activist rock star Juanes, and came two weeks after a diplomat incident following a Colombian military attack on Ecuadorean territory to kill a Colombian guerrilla leader. Ecuador and Venezuelan briefly sent troops to the Colombian frontier as a result.

The concert was held on the Simon Bolivar Bridge linking the Colombian town of Cucuta with Venezuela's San Antonio.

Top artists performing before the estimated 100,000 audience included Juanes and fellow Colombian star Carlos Vives, Ecuador's Fernando Velasco, Venezuela's Ricardo Montaner, Dominican Republic's Juan Luis Guerra, and Spaniards Alejandro Sanz and Miguel Bosé.

Union Radio broadcast the unique concert via radio, Internet and television to Colombia, Spain, Argentina, Chile, Mexico, Ecuador, Panama, Guatemala and Costa Rica to millions.

Union Radio has some 1,300 radio stations across Latin America. In Spain, the concert was Webcast live at PPV TV 40Latino's, and was broadcast on national radio Latin format network Cadena Dial, which has 1.7 million daily listeners, according to Estudio General de Medios (EGM).

Before the concert, Juanes said, "We want to consolidate the union between our peoples. We are brothers and sisters, we are equals. We just have to raise one flag together, the flag of peace".