Sofloff's family pays tribute

Sotloff's family paid a moving tribute to him on Wednesday, describing him as a "gentle soul" who was committed to giving a voice to the powerless.

The 31-year-old was decapitated in a gruesome act recorded on a video that came to light on Tuesday after it was posted by "Islamic State" (IS) militants. The footage was later confirmed to be genuine.

Sotloff family spokesman Barak Barfi said in a statement that the journalist had been drawn to the Middle East - and Syria where he was captured - through a fascination with the Arab world.

"He was no war junkie, he did not want to be a modern-day Lawrence of Arabia: he merely wanted to give a voice to those who had none," Barfi said.

"From the Libyan doctor who struggled with psychological services to children ravaged by war to the Syrian plumber who risked his life by crossing regime lines to purchase medicine, their story was Steve's story."

"He ultimately sacrificed his life to bring their story to the world," added Barfi. "Like all of us, he was a mere man who tried to find good concealed in a world of darkness and if it did not exist he tried to create it."

Journalist held two passports

Israel confirmed on Wednesday that the reporter - who had written for publications such as Time magazine, the Christian Science Monitor and the World Affairs Journal - held an Israeli as well as an American passport. The fact had been kept hidden from his captors for fear it would place him in further jeopardy.

Sotloff's murder followed that of reporter James Foley, who was executed by IS in August in what the group claimed was "retaliation" for US airstrikes against its fighters. In that video, an IS militant threatened that Sotloff would be the next to be killed.

'To the gates of hell'

US President Barack Obama, who has ordered in more troops to protect US interests in Iraq, said on Wednesday that his clear objective was to "degrade and destroy" Islamic State.

"We will not be intimidated. Their horrific acts only unite us as a country and stiffen our resolve to take the fight against these terrorists," the president said. "And those who make the mistake of harming Americans will learn that we will not forget, and that our reach is long and that justice will be served."

Speaking separately, from Maine, US Vice President Joe Biden declared that the US would pursue the militants to "the gates of hell."

Ahead of the NATO summit in Wales, where the threat from IS is likely to be discussed, British Prime Minister David Cameron said he was considering joining the nearly month-long US airstrike campaign against the group.

rc/lw (AP, AFP, dpa, Reuters)