Extremist group has been blamed for a weekend attack on a Kurdish wedding that left 54 dead

Turkey's army on Wednesday launched a pre-dawn operation involving fighter jets and elite ground troops to drive Islamic State extremists out of a key Syrian border town.

The operation, the most ambitious launched by Turkey in Syria conflict, was backed by US-led coalition airstrikes. It is aimed at clearing extremists from the town of Jarablus which lies directly opposite the Turkish town of Karkamis, the prime minister's office said.

Turkish President Recep Tayyip Erdogan said the operation aims to prevent threats from "terror" groups, including the Islamic State and a US-backed Syrian Kurdish militia that is affiliated with Turkey's outlawed Kurdish rebels.

In a speech on national TV, Erdogan said the operation was launched in response to a string of attacks in Turkey, including a suicide bombing at a wedding party near the border that killed 54 people last week.

The operation began at 4 am local time with Turkish artillery pounding dozens of IS targets around Jarablus.

Turkey has vowed to fight IS at home and to "cleanse" the group from its borders since the wedding massacre in southern Turkey. Officials have blamed IS for the attack.

'National security'

Tensions had flared across the Syria-Turkey border the previous day, following rocket fire from Jarablus which landed inside Turkey with the Turkish army firing howitzer rounds in response.

In an earlier interview with private NTV television, Deputy Prime Minister Numan Kurtulmus said Ankara saw Jarablus - "as a national security matter".

"What we have said, since the beginning, is that having Jarablus or any other city held by IS is unacceptable," he said.

Just a few hours after the operation started, US Vice-President Joe Biden landed in Ankara for talks that include developments in Syria.

Biden's visit comes at a difficult time for ties between the two NATO allies - Turkey is demanding that Washington quickly extradite a US-based cleric blamed for orchestrating last month's failed coup while Washington is asking for evidence against the cleric and that Turkey allow the extradition process to take its course.

Turkish F-16s bombed IS targets in Jarablus, the private NTV television reported, the first such assaults since a November crisis with Russia sparked when the Turkish air force downed one of Moscow's warplanes.

A dozen IS targets were completely destroyed in the airstrikes. Turkish artillery meanwhile destroyed 70 IS targets, television said.

Security sources quoted by Turkish television said a small contingent of special forces traveled a few kilometers into Syria to secure the area before a possible larger ground operation.

Television pictures showed Turkish tanks heading to the border but military sources told NTV they were changing place for security rather than crossing over.

NTV said that Russia had been informed of the action. Television pictures showed plumes of while smoke rising above Jarablus.

The incursion by Turkish special forces is the first such into Syria since February 2015, when hundreds of Turkish troops crossed the border to move the relics of the grandfather of the founder of the Ottoman Empire.