Gunmen killed 10 people including a Canadian tourist and police officers on Sunday in southern Jordan, before security forces killed four attackers in a siege lasting several hours.

The shootings took place in Karak, a tourist destination known for one of the biggest Crusader castles in the region, around 120 kilometres (70 miles) south of the capital Amman.

Jordan's general security department said seven policemen, a female Canadian tourist and two Jordanian civilians were killed in a series of shootings.

It said that 27 others, including policemen and civilians, were wounded.

Four attackers who had taken refuge in the castle were killed later Sunday by security forces who had besieged them amid exchanges fire lasting several hours, a security source said.

The Canadian foreign ministry confirmed that one of its nationals had been killed in the attack and another injured in "the heinous attack."

Canadian officials in Amman are "actively working with local authorities to gather additional information and are providing consular assistance to Canadians at this difficult time," a foreign ministry official said.

"The government of Canada stands ready to assist Jordan in bringing the perpetrators of this attack to justice," a statement added.

- 'Five or six gunmen' -

Earlier, the prime minister said 10 gunmen were holed up in the fortress, while the general security department spoke of "five or six gunmen" who were thought to be involved in the shootings.

The first attack took place early in the afternoon when a police patrol went to check on a house fire in Karak, the department said in a statement carried by the official Petra news agency.

"As soon as they reached the area, unknown gunmen who were inside the house opened fire on the patrol, wounding a policeman, and then fled by car," the statement said.

Gunmen later fired on another patrol while more shots rang out from inside the Crusader castle, aimed at the Karak police station and "wounding several policemen and passersby," it said.

"Police and security forces have surrounded the castle and its vicinity and launched an operation to hunt down the gunmen."

- People trapped -

A senior security source said some people had been trapped in part of the citadel when the gunmen took shelter there, but denied media reports that they were being held hostage.

"There are no hostages. But some people who were on a lower floor were afraid of leaving as the gunmen traded fire with the security forces," the source said, speaking on condition of anonymity.

He said that the gunmen were on a higher level inside the fortress.

The Jordan Tourism Board describes the Karak citadel, which dates back to the 12th century and has withstood many sieges, as a "maze of stone-vaulted halls and endless passageways."

Prime Minister Hani al-Malki, who was addressing parliament at the time of the shootings, said that "special forces and policemen are surrounding 10 gunmen holed up inside the Karak citadel."

It was not immediately clear who was behind the shootings, but Jordan has been hit by Islamist attacks in the past.

Jordan is a leading member of the US-led coalition fighting the Islamic State group in neighbouring Iraq and Syria.

It has carried out air strikes targeting IS, and also hosts coalition troops on its territory.

Maaz al-Kassasbeh, a Jordanian fighter pilot, was captured by the jihadists when his plane went down in Syria in December 2014, and he was later burned alive in a cage.

Karak is Kassasbeh's hometown.

In June, a suicide bombing claimed by IS killed seven border guards near the Syrian frontier.

According to sources close to Islamists, almost 4,000 Jordanians have joined jihadist groups in Iraq and Syria, and an estimated 420 have been killed since 2011.