WASHINGTON (Reuters) - President Barack Obama awarded 13 Americans on Thursday the 2011 Presidential Citizens Medal, the second-highest U.S. civilian honor, for service to the United States or fellow citizens.

Obama said the recipients had been chosen because, despite their different backgrounds, they had set examples of helping one's neighbors in keeping with American tradition.

"They could have chosen to do nothing. Instead, they chose to help," he said in a White House ceremony.

"The right choice is rarely the easy one," he added.

Obama selected those honored from nearly 6,000 nominations the White House received. The president called in May for the public to nominate people who had carried out exemplary deeds of service outside of their regular jobs.

Those awarded were:

-- Steve and Liz Alderman, Armonk, New York, founders of the Peter C. Alderman Foundation, set up to honor their son, who died in the September 11, 2001, attack on the World Trade Center. The foundation works to heal the emotional wounds felt by victims of terrorism and mass violence by training health care professionals. It has established clinics in countries that include Cambodia, Uganda, Rwanda, and Haiti.

-- Clarence Lee Alexander, Fort Yukon, Alaska, former grand chief of the Gwich'in people, for his work cleaning up the Yukon River.

-- Camilla Bloomquist, Penn Yan, New York, who has created and run many projects to help the poor and needy in Penn Yan, including food programs.

-- Judith Broder, Studio City, California, creator of the Soldiers Project, which seeks to meet the mental health needs of service members, their families and returning veterans.

-- Vijaya Emani, Strongsville, Ohio, an advocate for victims of domestic abuse, especially in the Indian American community. She died in a vehicle accident and wins the award posthumously.

-- John Keaveney, Los Angeles, a Vietnam combat veteran and founder of New Directions, a home for homeless and disabled veterans with addiction and mental health problems.

-- Roger Kemp, Leawood, Kansas, founder of the Ali Kemp Defense Education Foundation, which has trained more than 46,000 women in self-defense techniques. Kemp started the foundation after his daughter, Ali, was killed in 2002 by an attacker.

-- Janice Langbehn, Lacey, Washington, for efforts to revise hospital visitation rights for homosexual couples. Langbehn filed a federal lawsuit after she was refused hospital access to her partner, who died alone after a brain aneurysm.

-- Ida Martin, Bluffton, South Carolina, creator of Bluffton Self Help, which aids working families and disabled and elderly people with food programs and financial aid.

-- Margaret Martin, Los Angeles, founder of the Harmony Project, which provides musical instruments and lessons in impoverished areas of the city.

-- Michelle McIntyre-Brewer, Jefferson, Maryland, founder of Soldier's List, which supports service members and their families. The group has sent thousands of aid packages to help provide medical relief.

-- Roberto Perez, Miami, president of Alfalit, a non-profit organization combating illiteracy from Africa to South America. The group is credited with teaching 7 million people in 22 countries.

(Reporting by Ian Simpson)