PARIS — In a ceremony in Oslo that repeatedly invoked gender equality and the democratic strivings of the Arab Spring, the 2011 Nobel Peace Prize was presented to three female activists and political leaders on Saturday for “their nonviolent struggle for the safety of women and for women’s rights” as peacemakers.

To spirited applause and at least one ululating cry, diplomas and gold medals were presented to President Ellen Johnson Sirleaf of Liberia, 73; her compatriot Leymah Gbowee, 39, a social worker and a peace activist; and Tawakkol Karman, a Yemeni journalist and a political activist who, at 32, is the youngest Peace Prize laureate and the first Arab woman to receive the award.

“The promising Arab Spring will become a new winter if women are again left out,” said Thorbjorn Jagland, the chairman of the Norwegian Nobel Committee, who presided over the ceremony.

In her address, Mrs. Sirleaf said: “In its selection this year, the Nobel Committee has brought here three women linked by their commitment to change, and by their efforts to promote the rule of law and democracy in societies torn apart by conflict.”