NEW YORK - The chief suspect wanted for the double murder of a New York imam and his friend that sent shock waves through Muslim communities is in custody and charged with another crime, police said Monday.

Fearful Muslim New Yorkers have demanded stepped-up security and justice as hundreds of mourners attended their funeral service in the borough of Queens.

 Maulama Akonjee, 55, who migrated to the United States from Bangladesh, and his friend, 64-year-old Thara Uddin, were shot dead in broad daylight on Saturday afternoon in the Ozone Park neighborhood.

A 36-year-old Hispanic man from Brooklyn, whose name has not been released, is the chief suspect, police said.

"Because of the evidence we have acquired thus far, we strongly believe that this is the individual," Chief of Detectives Robert Boyce told a news conference.

Police said hate crime was being investigated as a possible motive - as demanded by Muslim elders - but said the motive was still unclear.

The suspect has been charged with a hit-and-run that took place three miles away from the murders and the assault of a police officer, Boyce said.

The suspect was in the area eight minutes before the homicide and took off directly afterward, Boyce said.

Officers will search his home later on Monday, looking for the murder weapon and the clothes worn by the killer, and witness line-ups are being organised, police said.

Police said the man came from East New York, a troubled area of Brooklyn, and was believed to have a job in a warehouse.

The New York Daily News quoted police sources as saying the killer may have been settling a score in a feud between Muslims and Hispanics, suggestions that have been dismissed by members of the Muslim community.

"We want justice, we want justice, we want justice," chanted Muslim elders at a chaotic news conference before Monday's funeral.

The Council on American-Islamic Relations offered a $10,000 reward for any information that could lead to the arrest or conviction of the perpetrators.

Community leaders, clearly rattled by rising Islamophobia, slammed "xenophobic statements" made against Muslims speech by "politicians and candidates seeking the highest office in the land" - a clear reference to Donald Trump.

Trump, the New York billionaire and Republican nominee, used a keynote address Monday to demand ideological screening tests for immigrants, saying immigrants had been responsible for a string of extremist attacks in America.

One speaker demanded security cameras be erected outside mosques and for the street where the two men were shot to be renamed in their honour.

Mayor Bill de Blasio, who paid his respects with other elected officials, promised extra police would protect mosques and Muslim communities, saying the entire city stood shoulder-to-shoulder with those in mourning.

 

"We will make sure that whoever did this is brought to justice, I can guarantee you that," de Blasio said.

 

"We know there are voices all over this country who are spewing hate, trying to create division, trying to turn one American against another," he said.

 

"We're not going to let them continue to encourage acts of hatred." Police on Sunday released a sketch of the suspect "with a medium complexion, last seen wearing a dark coloured shirt and blue shorts." The sketch showed a man wearing glasses with a beard and moustache, and a high forehead with his hair combed back.

 

The working-class area where the victims were killed, on the border between Queens and Brooklyn, is home to many Muslim families from Bangladesh.

 

Akonjee had been carrying more than $1,000, but the attacker did not take the money, police said.