Spain's new Prime Minister, Jose Luis Rodriguez Zapatero, has taken the oath of office at the Zarzuela Palace near Madrid, in a ceremony presided over by King Juan Carlos.
The socialist leader Saturday, recited the one-line oath with his right hand placed on the Spanish constitution.
The ceremony was attended by Queen Sofia and outgoing Prime Minister Jose Maria Aznar.
The 16 members of Mr. Zapatero's cabinet - eight men and eight women - are to be formally presented Saturday. They will be sworn in Sunday and meet for the first time on Monday.
Mr. Zapatero is Spain's fifth prime minister since democracy was restored following the death of the dictator General Francisco Franco in 1975. He was elected to office Friday by the Spanish parliament, by a 183 to 148 vote with 19 abstentions.
His Socialist Party won the national elections on March 14, defeating Mr. Aznar's party just three days after the March 11 Madrid commuter train bombings. Political observers say the government's response to those bombings and its pro-United States position on the occupation of Iraq are the primary reasons for the Socialists' victory.
Mr. Zapatero has pledged to withdraw Spain's troops from Iraq if the United Nations or some other international body does not take charge of the occupation by June 30. He also has promised a hard line on terrorism.