Slain U.S. journalist James Foley was living his faith by bringing images to the world of people suffering from war and oppressive regimes, a Roman Catholic bishop said Sunday at a mass in his honour.

Bishop Peter Libasci said even after Foley was captured for the first time in Libya in 2011, he "went back again that we might open our eyes."

The mass was attended by Foley's parents, John and Diane Foley, and hundreds of others in their hometown of Rochester, New Hampshire. The bishop read aloud a letter from the Vatican extending the condolences of Pope Francis. 

James-Foley-vigil

A vigil was held Saturday evening for James Foley in his hometown of Rochester, N.H., and a Mass was held Sunday to honour the freelance journalist slain by ISIS militants while covering the war in Syria. (Jim Cole/Associated Press)

Foley was kidnapped on Thanksgiving Day 2012 while covering the Syrian uprising. The Islamic State posted a Web video Tuesday showing his killing and said it was in retaliation for U.S. airstrikes in northern Iraq.

Libasci invoked the prayer of St. Francis, which begins, "Lord, make me an instrument of your peace," to implore the gathered not to hate but to heal.

"It is in giving that we receive," he recited. "It is in pardoning that we are pardoned. It is in dying that we are born to eternal life. To these words, I think we can say, `Yes, I wish we could do that.' It is not beyond our capability. It is not impossible. Our Lord lived it. Our most Blessed Mother lived it. Many saints have lived it. James lived it."

On Sunday, the British ambassador to the U.S. said his government was close to identifying the man who beheaded Foley. Peter Westmacott told CNN said his government was using voice-recognition technology to track down the man, who spoke with a London accent on the video.

U.S. President Barack Obama has called Foley a hero for telling the stories of oppressed people in war-torn regions like Syria and Libya. The U.S. launched a raid this summer to rescue Foley and other hostages, but special forces were unable to locate the captives.

In a packed Our Lady of the Holy Rosary church, the bishop frequently addressed Foley's parents and stressed their son's connection to family. He also prayed for another captive journalist, Steven Sotloff, and all captives.

"Jim went back again that we might open our eyes," Libasci said. "That we might indeed know how precious is this gift. May almighty God grant peace to James and to all our fragile world."

James Foley

Journalist James Foley was honoured Sunday at a Mass in Rochester, N.H. He was kidnapped and killed by ISIS militants while covering the war in Syria. (Nicole Tung/freejamesfoley.org/Associated Press)

A funeral for Foley will be Oct. 18, what would have been his 41st birthday.

Foley had "the courage to stand up bravely," Libasci told the crowd that was so large that people who couldn't find a seat in the pews stood along aisles.

A letter from the Vatican written to Foley's family was read at the closing of the mass, saying Pope Francis "joins all who mourn him [Foley] in praying for an end to senseless violence and the dawn of reconciliation and peace among all the members of the human family."

Captive journalist freed in Syria

Earlier on Sunday, an American journalist kidnapped nearly two years ago was freed in Syria, according to several news reports. 

Peter Theo Curtis was reported abducted in Antakya, Turkey in October 2012. He had planned to enter Syria.

U.S. Secretary of State John Kerry said in a statement that the United States was using "every diplomatic, intelligence and military tool" at its disposal to secure the release of other Americans held hostage in Syria.

The United Nations said it helped with the handover to UN peacekeepers in a village in the Israeli-annexed Golan Heights and that Curtis was released to American authorities after a medical checkup.

The administration provided no details about the circumstances of his abduction or his release. It was not known what prompted Curtis' release.

At a vigil Saturday night in Rochester, about 200 people gathered to show support for the Foley family. Foley's parents, John and Diane Foley, attended, Foster's Daily Democrat reported.

"We are honoured that you care and love Jim. We are honoured that you recognized the sacrifices he made," John Foley said. "He loved the Syrian people. He was devoted to telling their story and doing whatever he could to help their fight."

James Foley- Diane and John Foley

Diane and John Foley, seen here talking to reporters outside their home in Rochester, N.H., last week, thanked supporters at a vigil for their son Saturday night. (Jim Cole/Associated Press)

Speakers praised Foley's determination to report on the Syrian people uprooted by conflict.

"Tonight, we want to honour freedom and love: the freedom that James so vehemently believed that all people deserved," said Nadia Alawa, founder of NuDay Syria, a massachusetts-based organization working to ease the pain and loss in Syria. "To James Foley, denying others freedom and a basic voice of feelings and free space was not OK."

She also condemned the campaign of terror and violence carried out by the Islamic State.

"[ISIS] thrives on using the name of Islam to justify their vengeful acts that targets innocent non-Muslims as well as Muslims for no apparent, rational reasons," Alawa said. "As a Muslim, I refuse to let terrorists take my religion as hostage."

With files from Reuters and CBC News