A sacked security guard who shot one person and took about 30 others hostage at a Manila shopping centre on Monday surrendered to authorities, ending a day-long standoff.

The former guard walked out of the V-Mall where he was allowed to speak briefly to the press before heavily armed officers tackled and arrested him.

Scores of police officers in battle gear and carrying assault rifles amassed at the shopping centre in the Philippine capital, where the guard - who said he had a grenade - was barricaded with hostages in an office.

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One security guard was shot in the initial burst of violence and was rushed to hospital where he was in a stable condition, said Francis Zamora, mayor of the San Juan city, which includes the mall.

Zamora said about 30 to 40 people were being held, adding his estimate was based on the size of the administrative office where they were being held.

Zamora told reporters the hostage-taker - identified as Archie Paray - was upset after losing his job.

The suspect used his mobile phone to deliver a message to the guards and the media, expressing his anger over a change in his work hours and accusing his superiors of corruption.

A police officer holds a phone where the gunman is on a video call from inside a mall in San Juan city [Eloisa Lopez/Reuters]

Authorities spent hours trying to convince him to surrender, and held a press conference where company executives apologised for upsetting him.

Police were in contact with the suspect for hours via a walkie-talkie.

Philippine malls are centres of life that include everything from restaurants and shops, to churches and medical facilities. The building was full when the violence began.

Negotiations

Witness John Paul Buenavista told AFP news agency he saw a wounded person - believed to be a guard at the mall - being put into a wheelchair and whisked away.

"We heard three gunshots. Then we saw people running, saying they saw someone getting shot," he said.

Zamora said Paray had made several demands.

Paray later gave assurances the hostages would be released without harm, provided that the authorities did not try to trick him.

The gunman shows an apparent hand grenade on a video call with a policeman [Eloisa Lopez/Reuters]

Police spokesperson Virgilio Timajo said hundreds of shoppers and employees were evacuated from the mall in Manila's Greenhills shopping district after gunfire was heard from the second floor.

Al Jazeera's Barnaby Lo, reporting from outside the shopping mall, said "everything" took place inside the building's management's office.

The hostage-taker was fired from his job "not long ago and he encouraged his former colleagues to join him in sort of a mutiny against his former employers, but none of them joined him", Lo said.

Police officers block the area outside V-Mall where gunshots were fired in San Juan city [Eloisa Lopez/Reuters]

'They'll come out alive'

Late in the afternoon, a guard held up a smartphone to media during which the gunman panned his camera around the room to show the hostages were alive. He declined to say how many he was holding.

"Just wait, they will come out alive," he said.

Mall staff later handed out a few radios to reporters to allow them to ask the gunman questions.

Though major hostage incidents are rare in the Philippines, memories are fresh of when a sacked policeman hijacked a Manila bus full of Hong Kong tourists in 2010, and was killed in a gunfight together with eight passengers when police bungled a rescue attempt.