With less than 48 hours left in 2015, Turkey has become the latest country to announce foiling a holiday attack plot, detaining two suspected ISIS jihadists believed to be planning suicide bombings during New Year celebrations in the heart of the capital.

"They were caught before they had the opportunity to take action," said the office of the chief prosecutor of Ankara, Turkey's capital.

The prosecutor's office said the men had staked out possible locations in Ankara, where they could carry out the attacks.

The state-run Anadolu Agency, quoting unnamed police and judiciary officials, said the would-be-attackers were planning to detonate the bombs at two locations near bars and a shopping mall near Turkey's central Kizilay district during the celebrations.

"They were caught before they had the opportunity to take action," the prosecutor's office said.

The private NTV news channel, quoting security sources, said the two had "frequently" moved in and out of Syria and that security officials had been monitoring their movements for the past month.

Brussels cancels fireworks display

Elsewhere, Belgian authorities were investigating what authorities characterized as a "serious threat" of holiday season attacks directed at police, soldiers and popular attractions in the capital city of Brussels.

The arrest of two suspects was announced Tuesday by the Federal Prosecutor's Office, along with the seizure of military-style training uniforms, computer equipment and propaganda materials from ISIS. No weapons or explosives were found.

However, Brussels officials were sufficiently worried about the remaining risks that Mayor Yvane Mayeur announced Wednesday evening that a New Year's Eve fireworks display and related festivities planned Thursday in the city centre are being cancelled.

Last year, Mayeur told RTBF French-language television, 100,000 people turned out, and in current circumstances, he said, "we can't guarantee that we can check everyone."

Earlier attacks

In October, two suicide bombers detonated bombs outside Ankara's main train station as people gathered for a peace rally. The attack killed more than 100 people and was Turkey's deadliest. The prosecutor's office said the attack was carried out by a local cell of ISIS.

More than 30 people were also killed in a ISIS suicide attack in the town of Suruc, near Turkey's border with Syria, in July.

Earlier this year, Turkey agreed to take a more active role in the U.S.-led battle against ISIS. Turkey opened its bases to U.S. aircraft to launch air raids on the extremist group in Syria and has carried out a limited number of strikes on the group itself.

It has also moved to tighten security along its 900-kilometre border with Syria in a bid to stem the flow of militants.