British police said on Thursday they had charged a 26-year-old woman with being a member of the self-proclaimed Islamic State of Iraq and al-Sham (ISIS) and inciting terrorism on social media, after she was

The woman, from Burton upon Trent in central England who cannot be named for legal reasons, was arrested by counter-terrorism officers at London's Heathrow Airport in February after arriving on a flight from Turkey.

West Midlands Police said she had been charged with publishing messages on Twitter in October last year which encouraged people to commit or prepare acts of terrorism, and being a member of the banned organization ISIS.

She is due to appear before magistrates in London later on Thursday.

Some 700 Britons are estimated by the authorities to have travelled to Syria or Iraq, many to join ISIS, and on Wednesday police said they feared a family of 12 had been the latest to make the journey.

Cooperation between Turkish and U.K. police has intensified after three British girls, Shamima Begum, 15, Amira Abase, 15, and Kadiza Sultana, 16, went missing from East London in early February and reportedly arrived in Turkey to cross into Syria.

According to Turkish officials, Turkey has deported more than 1,100 Syria-bound foreigners back to their countries since January.

As part of Turkey's efforts, the police force has tightened security at transfer points such as airports, terminals, bus stations and rental car companies via a special risk analysis system, and a team tasked with tracking suspicious foreigners who travel to Turkey for the first time and those who are minors and who do not have a hotel reservation.

Those deported were of different origins varying in age from 15 to 35. The suspected foreigners claimed that the purpose of their visit was work, tourism or visiting friends or relatives, but security forces who had suspicions about the possibility of them joining ISIS sent them back to the countries where they had traveled from.