Madrid  - An advertising battle between atheists and believers expanded Monday in Spain as buses advocating the existence of God began running in Barcelona.

"When everyone abandons you, God stays with you," the Catholic association E-cristians said in an ad it had placed on a public bus. Two similar buses were due to start running shortly.

The buses were the answer of believers to two "atheist buses" carrying ads reading: "There's probably no God. Now stop worrying and enjoy your life."

The text is a translation of similar ads on London buses in a campaign launched by the British Humanist Association and prominent atheist scientist Richard Dawkins.

Spanish atheist groups staged a similar campaign in Barcelona, prompting a Protestant church to hit back in the Madrid region, where two buses show ads saying: "God does exist. Enjoy life in Christ." (dpa)