Britain has said it is facing the biggest terrorism threat in its history, in part because of the fear that British jihadists returning from Syria and Iraq could launch attacks on home soil.
More than 500 Britons are believed to have crossed into Iraq and Syria to fight with ISIL militants. Around half of those are thought to have returned to Britain.
Many extremists are believed to have used Turkey, which borders Syria and Iraq, as a transit point to travel to the region. In Ankara, Cameron said the highest-level intelligence sharing between the two countries could help stop the flow of jihadists in and out of Syria.
"The prime minister and I have agreed we should exchange even more information, we should cooperate more in terms of intelligence," he said.
"We should work hand in glove because the people who are travelling whether from Britain or elsewhere... these are people that threaten us back at home, so we should do everything we can," he added.
"This is all about making sure people are safer in Turkey, and making sure people are safer back home in the United Kingdom."
He said the talks also focused on a "long-term strategy to defeat ISIL and to restore stability in this part of the world."
"What we need in Iraq is what we need in Syria. We need to see new government that represents all of the people," Cameron said.
Faced with the threat of fighters returning home, Britain is planning to toughen its laws to stop potential jihadists from leaving home.
Those include measures to seize passports from British jihadists, stopping them returning from fighting overseas, and proposing landing bans on airlines that fail to comply with London`s no-fly lists.
Davutoglu rebuffed international criticism that Turkey, a vocal critic of Syrian President Bashar al-Assad`s regime, has tolerated radicals to pass through its territory to fight in Syria.
"No single ISIS (fighter) has crossed via Turkish soil," he said, branding ISIL as a "threat" to Turkey`s national security.
"Nobody can dispute Turkey`s determination in the fight against terrorism," he added.
"Turkey`s position is clear: We don`t want to see foreign fighters, neither in Syria nor in Iraq." Turkey wants a wider strategy for Syria that would ultimately bring the downfall of Assad. It has repeatedly called for a buffer zone, backed by a no-fly zone, to be put in place inside the war-torn country on the Turkish border.
Cameron later went into a dinner for talks with President Recep Tayyip Erdogan at his grandiose new presidential palace.
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