Washington — More than 1.1 billion people worldwide signed on to a social media campaign commemorating World Humanitarian Day, recognized each year on August 19.

Pop star Beyoncé loaned her celebrity to the campaign, dubbed “I Was Here,” urging people to perform some act large or small to help others.

“I Was Here” is also the name of the video that Beyoncé filmed in the meeting chamber of the U.N. General Assembly earlier in August as part of the campaign. Dressed in a glittering white gown, Beyoncé sings about the importance of leaving a mark in the world, as she stands where notable moments in world diplomatic history have unfolded. On a giant screen behind the performer, film footage of humanitarian action in the midst of war, flood and other disasters unfolds.

In 2008 the General Assembly called for commemoration of World Humanitarian Day each year on August 19, the date when a terrorist attack on U.N. headquarters in Baghdad in 2003 killed 22 people, including U.N. envoy Sergio Vieira de Mello. He was serving as the secretary-general’s special representative in Iraq at the time, his final post in a 34-year U.N. career.

“World Humanitarian Day honors those who have lost their lives in humanitarian service and those who continue to bring assistance and relief to millions,” according to the U.N. description of the occasion.

With a recent trip to Turkey in mind, U.S. Secretary of State Hillary Rodham Clinton framed her remarks for the event around the growing problem of Syrian refugees in neighboring countries. Anyone who has helped these refugees find haven is a humanitarian, she said.

“The average Turkish citizen may not have volunteered to be a humanitarian — they just happen to live near the crisis,” Clinton said. “But they have accepted their Syrian neighbors with open arms and have assumed the duty of protecting them. The same is being done in Jordan, Lebanon and Iraq.”

In a statement from the White House, press secretary Jay Carney honored the memory of more than 1,000 humanitarian workers who have lost their lives in humanitarian service in the past 15 years.

“Since last August, 272 aid workers have been killed, injured or kidnapped,” Carney said. “As armed groups increasingly target humanitarians, the United States condemns any effort to harm aid workers and demands that they be given the access they need to reach those in need and save lives.”

Carney also criticized the Syrian regime for restricting the delivery of humanitarian aid to 2.5 million people who need help.

In her statement, Clinton gave a name and identity to the death statistics among humanitarian workers. She saluted the dedication of Ragaei Abdelfattah, a U.S. Agency for International Development (USAID) officer who was killed in early August by terrorists in Afghanistan’s Kunar Province. Several members of the International Security Assistance Force and Afghan civilians also died in the incident, according to USAID.

“We were shocked and saddened by this loss,” Clinton said. “But we must continue the work that he so passionately believed in.”