Ireland stands united in grief with the US after its ambassador in Libya was killed on the anniversary of 9/11, Tanaiste Eamon Gilmore has said.
The Foreign Affairs minister condemned the killing of Christopher Stevens and three colleagues during an attack on the embassy in the eastern city of Benghazi over a US-produced film said to ridicule Islam and the prophet Mohammed.
US president Barack Obama described the assault by an armed mob as callous and praised the victims who "exemplified America's commitment to freedom, justice, and partnership with nations and people around the globe".
Mr Gilmore said: "Ambassador Stevens and his colleagues died on the eleventh anniversary of 9/11. Sadly, hatred and extremism continue to blight our world. We must not follow those who take this path. We must stand together against them.
"Ireland stands with the people of the United States in this moment of grief. We stand with the government of Libya at this time of challenge. We stand with all those in the Arab world who promote peace, democracy, tolerance and human rights in this region at this time of historic change."
Mr Stevens was reportedly killed when a rocket hit his car, although there are conflicting reports about whether he lost his life in the initial incident or as he returned to the scene.
The US embassy in Cairo was also targeted earlier in the day but no one was injured.
Mr Gilmore conveyed his condolences and those of the Irish Government and people to the bereaved and to the people of the US.
"I also wish to condemn, in the strongest possible terms, the attack on the US consulate in Benghazi yesterday, which led to Ambassador Stevens's death and those of his colleagues," he said.
"Attacks on diplomatic missions are completely unacceptable and cannot be justified in any terms."