About 3,500 Yazidi women and children have been coerced into sexual slavery, sold to Islamic State fighters for "between $500 and $2,000," or given out as prizes in Koran memorization competitions.
A report released in May by Amnesty International on the use of barrel bombs in Aleppo concluded that they had killed 3,000 civilians and 35 fighters between January 2014 and March 2015.
The ability to enforce these measures to stem the flow of foreign fighters between Britain to Syria will depend on the enforcement of no-fly lists across Europe.
Opposition fighters said that after a pitched battle lasting several hours, they had seized control of a vital checkpoint northwest of the city, in Anadan, freeing up a route for supplies and fighters between Aleppo and the Turkish border.
The two principal Kurdish political parties, which have administered a region that broke away from the Baghdad government in 1991, have long claimed as many as 50,000 regular fighters between them, and almost as many in reservist militias.
Military experts say the two forces have no more than 2,500 well-trained fighters between them, far too few to fight effectively on both fronts at the same time.
Based on their populations, the figures for Belgium, the Netherlands and Ireland, with about 200 fighters between them, made these countries the most significant, the lead researcher, Prof Peter Neumann from the International Centre for the Study of Radicalisation (ICSR) at King's College, said.
"Numbers since 2010 are now many times the size of the cumulative numbers of foreign terrorist fighters between 1990 and 2010 – and are growing," says the report, produced by a security council committee that monitors al-Qaida.
Peter Cook, the Pentagon's press secretary, described Chouchane as an Isis "senior facilitator" who aided the movement of foreign fighters between his home country of Tunisia, the targeted training camp in Libya and onward to other countries.
