By Tulay Karadeniz and Angus McDowall
ANKARA/BEIRUT (Reuters) - Turkey's military said on Friday it was close to taking Syria's al-Bab from Islamic State, but a war monitor said the jihadists still controlled 90 percent of the town itself and that shelling and air strikes had killed dozens of civilians in recent days.
Al-Bab, an Islamic State stronghold 30 km (20 miles) from the Turkish border, has been a prime target since Turkey launched an incursion last August to push the jihadists from its frontier and prevent gains by a Kurdish militia also fighting them.
Taking control of the town would deepen Turkish influence in an area of Syria where it has already effectively created a buffer zone and allow Turkish forces to press on towards Raqqa, Islamic State's de facto capital in Syria.
"The operation to gain complete control of the al-Bab region has neared its end and the resistance of the Daesh terror group has largely been broken," the Turkish military statement said, using an Arabic acronym for Islamic State.
However, the Syrian Observatory for Human Rights, a British-based organization that monitors the war using a network of contacts, said Turkey's "Euphrates Shield" forces had not made much progress.
Islamic State still controls 90 percent of al-Bab town itself and Turkish shelling and air strikes had killed 45 civilians, including 18 children, during the past 48 hours, the Observatory said.
Turkish officials have repeatedly said that the al-Bab operation was taking longer than anticipated because of numbers of civilians still in the town and the care being taken not to harm them. It dropped leaflets on the town as long ago as December urging civilians to seek shelter.
Turkey believes a string of Islamic State gun and bomb attacks, including a mass shooting at an Istanbul nightclub on New Year's Eve, were planned from al-Bab and Raqqa, and has said clearing the town of militants is a national security priority.
The military statement came as U.S. Marine Corps General and Chairman of the Joint Chiefs Joseph Dunford visited the Incirlik air base in southern Turkey, used by the U.S.-led coalition in the fight against Islamic State.
Turkey is part of that coalition but relations with NATO ally Washington have been strained by U.S. support for the Kurdish YPG militia in the fight against Islamic State.
Turkey views the YPG as a hostile force and an extension of the PKK, a Kurdish militant group that has waged an armed insurgency against the Turkish state for over three decades.
"It is time the U.S. leadership made clear who they are cooperating with in their Syria policy," a senior Turkish government official told Reuters, when asked about the possibility of U.S. combat troops being deployed to Syria under President Donald Trump.
"U.S. soldiers are present in Syrian territory, and we saw the results. They trained the PKK-YPG, which we call a terrorist organization, gave them weapons and supported terrorist groups."
President Tayyip Erdogan has said the next target for the Turkish offensive should be Raqqa but that Arab forces, not the YPG, should be involved.
The Syrian Democratic Forces, an alliance dominated by the YPG, is in the middle of a multi-phased operation to encircle Raqqa, backed by air strikes and special ground forces from the U.S.-led coalition.
(Additional reporting by Orhan Coskun and Ece Toksabay; Writing by Nick Tattersall; Editing by Daren Butler and Angus MacSwan)