ANKARA (AFP) - Turkey accused Britain of a "reprehensible" delay in informing the Turkish authorities over the departure to its territory of three teenage girls feared to be en route to Syria.

The three girls, aged between 15 and 17, boarded a flight from London to Istanbul last Tuesday and police suspect they were on their way to join Islamic State in Iraq and Syria (ISIS).

"It is a reprehensible act for Britain, a country famous for its Scotland Yard, to let the three girls... leave Heathrow airport (London) for Istanbul and then let us know three days later," Deputy Prime Minister and government spokesman Bulent Arinc told Turkish reporters late Monday.

"Turkey cannot be held responsible for what happened," he added. "We don't have a mechanism in place that allows us to question the intentions of tourists and read their minds."

London's Metropolitan Police, also known as Scotland Yard, responded saying they had informed authorities the day after they disappeared.

"Once we established that the girls had travelled to Turkey, police made contact with the foreign liaison officer at the Turkish embassy in London on Wednesday, 18 February," police said in a statement.

"Since then we have been working closely with the Turkish authorities who are providing great assistance and support to our investigation."

But Arinc said Britain had failed to take the "necessary measures" and that it "should have informed us and shared intelligence with us".

Turkey has repeatedly been accused by its Western allies of failing to do enough to stop the transfer of militants, as well as their female companions, across its territory on their way to Syria.

Arinc's complaints echo similar remarks made by Turkish officials after Hayat Boumeddiene, the wanted partner of one of the gunmen behind the January terror attacks in France, travelled undetected through Turkey on her way to Syria.

In that case, Ankara accused the French authorities of failing to share information in a timely manner about the wanted woman's departure for Turkey.

British anti-terror police made an unprecedented appeal on Friday to find the three girls, two of whom are British and the third a German citizen.

Richard Walton, head of the police's Counter Terrorism Command, said he was "extremely concerned" for the well-being of the girls, who were all close friends studying at Bethnal Green Academy in east London.

An estimated 550 Western women have travelled to join the militants in Iraq and Syria.