Letters slain journalist Steven Sotloff wrote to his family before he was beheaded by Islamic State militants were read at his memorial service on Friday, with him telling them to be happy and stay positive and that if they didn't meet again, he hoped they would in heaven.

Several hundred mourners attended the service at Temple Beth Am in suburban Miami, including Senator Marco Rubio. He told the gathering that Mr Sotloff unmasked 'the nature of what we are dealing with' in final moments of his life.

The service was arranged as quickly as possible, keeping with Jewish custom - even though Mr Sotloff's body is not there.

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Mourners embrace before entering a memorial service for freelance journalist Steven Sotloff at Temple Beth Am in Pinecrest, Florida on Friday. The 31-year-old was shown being beheaded by an ISIS militant in a video posted online on Tuesday

Mourners, including Senator Marco Rubio, gathered in their hundreds today, to bid farewell to journalist Steven Sotloff who was murdered by Islamic extremists after being taken hostage in Syria a year ago

Devastated mourners gathered at Temple Beth Am in suburban Miami. The state governor Rick Scott had ordered flags flown at half-mast for Steven Sotloff today

The U.S. State Department has offered no information on the possibilities of recovering the bodies of Steven Sotloff and fellow slain journalist James Foley.

The State department would not comment when contacted by Mailonline today.

There was heavy security at Friday's service, with officers stationed at the front gate and entrance of the building in Pinecrest.

'Our job is to help them grieve, and that's what we're here to do as a family,' the temple's executive director Robert Hersh said before the service for Mr Sotloff today.

He said the family will sit shiva, the Jewish mourning period, Saturday, Sunday and Monday.

Organisers distributed a sheet of paper with the lyrics to a song Mr Sotloff's sister, Lauren Sotloff, had chosen - 'Wish You Were Here' by Pink Floyd.

Mr Sotloff attended the temple school as a child, and his mother, Shirley Sotloff, teaches preschool there.

Police officers stand at the front gates at a memorial service for U.S. freelance journalist Steven Sotloff

Mourners entered the memorial service on Friday with flowers to remember the life of Steven Sotloff

Mr Sotloff, a 31-year-old who freelanced for Time and Foreign Policy magazines before he was captured in Syria a year ago, also was an Israeli citizen.

That fact was not widely known before his death - in part because Israel's military censor apparently kept a lid on the story for his safety.

Mr Sotloff was remembered by his loved ones as a journalist who wanted to give a voice to the weak and the suffering

His killers are not believed to have known about his background.

Rabbi Solomon Schiff said on Friday that Sotloff was the grandson of Holocaust survivors who 'knew after their bitter experience that only education can change hearts'.

Mr Sotloff was close to them, and developed an interest in social justice issues.

He became fluent in Arabic, read passages of the Quran and 'felt the suffering of those who live under despotic dictatorships, which is why he wanted to tell their stories,' Rabbi Terry Bookman said.

Mr Sotloff visited Israel in the summer of his freshman year of college at the University of Central Florida, and later decided to pursue a counterterrorism study program there, despite his family's fears, Shirley Sotloff said.

'Though aware of the danger, his confidence in the goodness that lies in each person's core helped him overcome his anxiety and fear,' Bookman said.

Mr Sotloff's sister, dressed in black and wearing sunglasses, read a short letter she wrote for her brother.

In it, she described how he was her best friend and how they could be happy together 'doing absolutely nothing.'

'You were the one who brought music into my life,' Lauren Sotloff said before burying her hands in her face in tears.

A woman leaves in tears from the emotional memorial today where Mr Sotloff's letters to his family were read out to mourners

The 31-year-old was remembered as a man with a deep interest in social justice issues who wanted to give a voice to the voiceless

Steven Sotloff's mother Shirley appealed to the captors of her son to release him last month but her pleas went unanswered and he was brutally killed

She then played a recording of a song that reminded her of him: 'Wish You Were Here' by Pink Floyd. As the song played, many in the audience sang along.

Mr Sotloff is one of two American journalists the Islamic State has held captive and beheaded for what militants called payback for more than 120 U.S. airstrikes on its assets in northern Iraq since August 8.

Journalists James Foley and Mr Sotloff were two of what the State Department has described as 'a few' Americans still being held hostage by the group. The Islamic State also had threatened to kill a British man it is holding hostage.

Before he died, Mr Sotloff managed to get two letters to his family, a cousin said.

'Everyone has two lives,' he wrote in one. 'The second one begins when you realise you only have one.'

He urged his family to hug one another, eat dinner together and surround themselves with strong and wise people.

The last letter was sent in May. Four months later he was killed.

Florida Governor Rick Scott, right, shakes hands with an unidentified man as he leaves a memorial service for US freelance journalist Steven Sotloff at Temple Beth Am in Pinecrest today

Senator Marco Rubio attended Mr Sotloff's memorial today and told the gathering that Sotloff unmasked 'the nature of what we are dealing with' in final moments of his life

Mr Sotloff, a 31-year-old who freelanced for Time and Foreign Policy magazines before he was captured in Syria a year ago, also was an Israeli citizen

The Islamic State has beheaded two American journalists it held captive for what the militants called payback for more than 120 U.S. airstrikes on its assets in northern Iraq since August 8.

Journalists James Foley and Steven Sotloff were two of what the State Department has described as 'a few' Americans still being held hostage by the group.

The Islamic State also had threatened to kill a British man it is holding hostage.

In a statement on Wednesday, a family spokesman said Mr Sotloff dedicated his life to portraying the suffering of people in war zones, but was 'no hero'.

Family spokesman Barak Barfi told reporters gathered outside the family's suburban Miami home that Sotloff 'tried to find good concealed in a world of darkness,' and to give voice to the weak and suffering in the Arab world.

Mr Barfi said Mr Sotloff was 'no war junkie,' but was drawn to the stories of the turbulent Middle East, and his family has pledged to 'not allow our enemies to hold us hostage with the sole weapon they possess - fear.'

Attendees and police are seen in front of Temple Beth Am where journalist Steven Sotloff was remembered as a man 'who felt the suffering of those who live under despotic dictatorships'