US Secretary of State John Kerry Friday mourned diplomatic staff lost in global conflicts, including two killed in the Vietnam War, adding eight names to an already-long and somber memorial plaque.
Four people honored in Friday's ceremony were slain in the September 11 militant assault on a US mission in Libya, two were killed in bombing attacks in Afghanistan, and two others died some four decades ago in Vietnam.
"Each one sought out the most difficult assignments. They understood the risks, and still they raised their hands and they said: 'Send me,'" said Kerry as the names were unveiled and added to more than 230 already carved into a plaque in the State Department building entrance.
"It's a hard day. It's a day that brings back pain. But it's also a day, I hope, of comfort and of pride in knowing that the contributions and the memories of your loved ones are a permanent part of the State Department, as strong as the marble which will carry their names for eternity."
Those remembered included ambassador Chris Stevens killed in the Benghazi attack along with information technology specialist Sean Smith, former navy SEAL Glen Doherty and diplomatic security officer Ty Woods.
The youngest was Anne Smedinghoff, 25, who died in a bombing in the southern Afghan province of Zabul as she was delivering books to Afghan schoolchildren.
Ragaei Said Abdelfattah, who worked for the US development agency USAID, was killed in a suicide bombing in Kunar province, Afghanistan last August.
The State Department also paid tribute to foreign service officers Joseph Fandino and Francis Savage, who both died in the Vietnam War more than 40 years ago, and whose families had raised their cases.
Earlier at a separate event to mark Foreign Affairs Day, Kerry listed the huge task facing US diplomats today.
"North Korea, Afghanistan Pakistan, rising groups of terrorists in various parts of the world," including Africa and the Arabian peninsula, all posed challenges, he said.
And in Iran there was "the very real potential of conflict and its consequence of the lack of transparency of the nuclear program."
Vice President Joe Biden joined the memorial ceremony, praising the "incredible heroism" of those who were lost.
"There are people today who are in harm's way, as significant -- as I've said (as) any one of our soldiers stationed anywhere in the world," Biden said.
To answer critics who have called for the US to retreat from its global footprint, Biden insisted: "America's presence is required."
But he vowed, amid a fierce polemic in the US after the Benghazi attack, that "everyone in our government knows we have a solemn obligation to do more and more to protect" the nation's diplomats.