Ukrainian police say the armed man who took 13 people aboard a long-distance bus in the western city of Lutsk hostage on Tuesday morning has been detained after authorities stormed the vehicle. 

"The hostages are freed! The man who took the hostages and kept them on a bus in Lutsk has been detained," the Interior Ministry posted on Telegram late Tuesday following a 10-hour stand-off with the assailant. 

Interior Minister Arsen Avakov tweeted several pictures and a video showing the hostages being led to safety and a photograph of the detained man lying on the ground surrounded by armed officers.

The country's SBU Security Service said no one was injured in the incident. 

Earlier in the evening, three of the hostages were released, including "an elderly woman, a teenager and a pregnant young woman," Ukraine's Deputy Interior Minister Anton Gerashchenko said. 

Armed police move in

A man with explosives and weapons seized the bus and took 13 people hostage in northwestern Ukraine early Tuesday morning, the SBU said in a Facebook statement.

Police had earlier put the number of hostages at 20. It remains unclear how many people were on board the bus when it was seized at 9:25 a.m. local time (0625 UTC), or whether any hostages initially managed to escape. 

Read more: Netherlands to take Russia to European court over MH17 downing

Authorities blocked off the city center of Lutsk, some 400 kilometers (250 miles) west of Kyiv, and asked locals to remain inside their homes or places of work as officers held negotiations with the armed man. 

Video footage of heavily armed police surrounding the bus was published by local media.

"The attacker threw a grenade from the bus, which, fortunately, did not detonate," the SBU statement read. Ukrainian media reported that gunshots had been heard at the scene, which was also confirmed by President Volodymyr Zelenskiy.

"Gunshots have been heard, the bus is damaged," Zelenskiy said in a statement posted on Facebook.

The prosecutor general's office said the hostage-taker had claimed a separate explosive device was located in a public place in the city of around 200,000 residents which could be detonated remotely. 

Past criminal record

Earlier in the day, the 44-year-old man called authorities himself after taking control of the bus and introduced himself as Maksym Plokhoy — a pseudonym which translates to "bad Maxim" — Deputy Interior Minister Anton Gerashchenko said on Facebook. 

Authorities identified the individual shortly afterwards and said that he had previously vented his anger with "Ukraine's system" via social media.

Complying with the hostage-takers demands, Zelenskiy posted a six-second video urging the public to watch the 2005 film 'Earthlings,' a movie about mankind using animals for pets, food and clothing.

"Everyone should watch the 2005 film 'Earthlings,'" he said in the video posted to his Facebook page, which has been since deleted.

Gerashchenko added the man had previously spent around 10 years in prison for a variety of offences, including fraud and illegal handling of weapons.

Read more: Ukraine's surrogacy industry leaves parents in limbo

This is an updated version of a previous article.

jlw,jsi/msh (AP, AFP, dpa)