SYDNEY: A gunman at the centre of a 16-hour siege in a Sydney cafe was one of three people killed when heavily armed security forces stormed the building following an exchange of gunfire, Australian police said on Tuesday.

No explosives had been found and 17 hostages had been accounted for, Andrew Scipione, police commissioner for the state of New South Wales, told reporters.

Police said that a 34-year-old man and a 38-year-old woman died during the hostage crisis. Four other people were injured.

Earlier on, a swarm of heavily armed police stormed the Sydney cafe, ending the siege.

A police spokesman confirmed “the operation is over,” but would not release any further details about the fate of the gunman or his remaining captives.

After a flurry of loud bangs, police swooped into the Lindt Chocolat Cafe shortly after five or six hostages were seen running from the building.

After the police moved in, one weeping woman was helped out by the officers and at least two other people were wheeled out on stretchers.

The dramatic scene unfolded shortly after the gunman was identified by local media as Iranian-born Man Haron Monis, who is facing charges including sexual assault and accessory to murder in separate cases.

A police official said “you wouldn't be wrong” in identifying the 50-year-old Monis as the gunman. Under department rules, officials do not identify themselves unless speaking at a formal news conference.

Monis has long been on officials' radar. Last year, he was sentenced to 300 hours of community service for writing offensive letters to families of soldiers killed in Afghanistan.

He was later charged with being an accessory to the murder of his ex-wife. Earlier this year, he was charged with the sexual assault of a woman in 2002. He has been out on bail on the charges.

“This is a one-off random individual. It's not a concerted terrorism event or act. It's a damaged goods individual who's done something outrageous,” his former lawyer, Manny Conditsis, told Australian Broadcasting Corp.

“His ideology is just so strong and so powerful that it clouds his vision for common sense and objectiveness,” Conditsis said.

Throughout the day, several people were seen with their arms in the air and hands pressed against the window of the cafe, and two people holding up a black flag with the Shahada, or Islamic declaration of faith, written on it.

Militants have used the Shahada in their own black flag. A number of Australian Muslim groups condemned the hostage-taking in a joint statement and said the flag's inscription was a “testimony of faith that has been misappropriated by misguided individuals.”

In a show of solidarity, many Australians offered on Twitter to accompany people dressed in Muslim clothes who were afraid of a backlash from the cafe siege.

The hashtag #illridewithyou was used more than 90,000 times by late Monday evening. Seven Network television news staff watched the gunman and hostages for hours from a fourth floor window of their Sydney offices, opposite the cafe.

Armed tactical response officers enter the building after shots were fired during a cafe siege in the central business district of Sydney. -AP Photo

The gunman could be seen pacing back and forth past the cafe's windows. Reporter Chris Reason said the man carried what appeared to be a pump-action shotgun, was unshaven and wore a white shirt and a black cap.

Earlier Monday, network staff counted about 15 different faces among hostages forced up against the windows.

“The gunman seems to be sort of rotating these people through these positions on the windows with their hands and faces up against the glass,” Reason said in a report from the vantage point.

“One woman we've counted was there for at least two hours, an extraordinary, agonizing time for her surely having to stand on her feet for that long.”

“When we saw that rush of escapees, we could see from up here in this vantage point the gunman got extremely agitated as he realized those five had got out. He started screaming orders at the people, the hostages who remain behind,” he added.

Reason later reported that staff brought food from a kitchen at the rear of the cafe and the hostages were fed. As night set in, the lights inside the cafe were switched off. Armed police guarding the area outside fitted their helmets with green-glowing night goggles.

St. Vincent's hospital spokesman David Faktor said a male hostage was in satisfactory condition in the hospital's emergency department. He was the only one of the freed hostages to be taken to a hospital, and Scipione said he was being treated for a pre-existing condition.

Hundreds of police blanketed the city as streets were closed and offices evacuated. The public was told to stay away from Martin Place, site of the state premier's office, the Reserve Bank of Australia, and the headquarters of two of the nation's largest banks.

The state parliament house is a few blocks away, and the landmark Sydney Opera House also is nearby.

“This is a very disturbing incident,” Prime Minister Tony Abbott said.

“It is profoundly shocking that innocent people should be held hostage by an armed person claiming political motivation.”

Lindt Australia posted a message on its Facebook page thanking the public for its support.

“We are deeply concerned over this serious incident and our thoughts and prayers are with the staff and customers involved and all their friends and families,” the company wrote.

Australia's government raised the country's terror warning level in September in response to the domestic threat posed by supporters of the Islamic State group.

Counterterror law enforcement teams later conducted dozens of raids and made several arrests in Australia's three largest cities; Melbourne, Sydney and Brisbane.

One man arrested during a series of raids in Sydney was charged with conspiring with an Islamic State leader in Syria to behead a random person in downtown Sydney.

The Islamic State group, which now holds a third of Syria and Iraq, has threatened Australia in the past.