VALENCIA, Spain — Pope Benedict XVI’s visit to Spain ended on an awkward note yesterday when Prime Minister Zapatero failed to attend his valedictory Mass in Valencia.

More than a million worshippers congregated at the city’s futuristic arts and science park, where the pope gave a homily praising the traditional family founded on the “indissoluble marriage between a man and a woman.”

In a veiled attack on the liberal laws introduced by Mr. Zapatero’s socialist government since it came to power two years ago, the pontiff said: “In contemporary culture, we often see an excessive exaltation of the freedom of the individual.”

Mr. Zapatero’s government has been at loggerheads with the Roman Catholic Church over a domestic program of radical legislation that includes giving marriage and adoption rights to homosexuals and relaxing divorce laws.

Pope Benedict urged the worshippers, who included King Juan Carlos and Queen Sofia, to join forces with church organizations in the “promotion of the authentic good of the family in contemporary society.”

A spokesman for the government, Fernando Meraleda, said heads of state were not expected to attend such events.

However, this is the first time in Spanish history that a religious ceremony presided over by a visiting pope has not been attended by the country’s leader.

Local press reported that Mr. Zapatero’s decision caused a “certain irritation” in the papal entourage.

Mr.Zapatero did not ignore the pope’s presence entirely. On Saturday afternoon, he attended a 15-minute private audience with the 79-year-old pontiff.