On Wednesday evening, Vital Voices saved their surprise guest for the finale of the annual Global Leadership Awards at the Kennedy Center Opera House. She delivered a surprise speech in return.

Yemen activist Tawakkol Karman uses Facebook to mobilize supporters on Feb. 10, 2011. (Sudarsan Raghavan/The Washington Post)

After the winners of the Global Trailblazer award — women activists who have become symbols of the Arab uprisings — finished their speeches, Tawakkol Karman, the Yemeni journalist and co-recipient of the 2011 Nobel Peace Prize, stepped on stage. Karman, 33, the first Arab woman to win the prize, reminded the audience why these activists are being recognized for voicing their opinions without reservation. After beginning with the solemn, polite words often expected at Washington awards shows, she led the crowd in an unexpected chant.

“One, two, three, four. Bashar al-Assad out the door,” she yelled from the stage, encouraging the crowd to join.

The moment was met with some nervous laughter, but she continued the chant and encouraged the audience to join her. For less than a minute, diplomats, government officials, journalists and students took part in the sort of chant that Karman is known for, the ones she led during the Yemeni uprisings.

“Chant is the soul of the revolution, the whole Arab Spring,” she said at a supper following the awards. “Chant is needed when we are in the streets, in front of the bombs and the violence. This voice is our voice, and it is successful and more powerful than dictators.”

Her chant was particularly poignant in light of reports of civilian killings Wednesday in the Syrian province of Hama. Reports said that as many as 78 civilians were slain by pro-government militias. On Thursday, U.N. Secretary-General Ban Ki-moon condemned the deaths as “an unspeakable barbarity.”

Karman, who is in the United States to give a speech at Harvard University on Thursday, is hoping that the U.S. will push for sanctions against the Syrian government. “If America does it, other countries will follow.”

In 1997, Vital Voices Global Partnership was started by then-first lady Hillary Clinton and then-Secretary of State Madeleine Albright to empower female leaders across the world. It has trained more than 12,000 women from 144 countries. Washington Post Staff writer Emily Wax spent the weekend with the honorees as they visited tourist sites around Washington, capturing how these women advocates bonded and shared their experiences.

The annual awards event honored a variety of human rights activists, including Manal al-Sharif. Al-Sharif made a viral video of herself behind the wheel of a car in Saudi Arabia, where custom prohibits women from driving. She could not attend the event for fear that she would face repercussions for leaving the country.

Others were honored for their service in human rights, politics and business. Rosana Schaack of Liberia received the Human Rights Award. In 2003, she started the nonprofit Touching Humanity in Need of Kindness (THINK) to provide rehabilitation homes and services to former girl soldiers forced to fight or serve as sex slaves during the Liberian Civil War. Adimaimalaga Tafuna’I, an entrepreneur from Samoa, founded Women in Business Development Inc. and has worked to bring local resources, such as organic coconut oil, to global markets. And Ruth Zavaleta Salgado of Mexico, a founder of Mexico’s Party of the Democratic Revolution, was recognized for her political leadership as the first female PRD politician to serve as president of the Mexican Chamber of Deputies.

Notable attendees, including Wolf Blitzer, Claire Shipman, Andrea Mitchell, Sen. Kay Bailey Hutchison (R-Tex.), Tina Brown and Diane von Furstenberg, spoke and presented awards to the recipients. Chelsea Clinton stood in for her mother, who was unable to attend for the first time in 11 years.