Smugglers who used to make a living helping the Islamic State bring foreign fighters into Syria say that it is increasingly difficult — though still not impossible — to do so now. Border guards who once fired warning shots, they say, now shoot to kill.

“Whoever approaches the border is shot,” said Omar, a smuggler interviewed in the border town of Kilis who insisted on being identified by only his first name because of the illegal nature of his work. “And many have been killed.”

Another smuggler, Mustafa, who also agreed to speak if only his first name was used, said, “Two months ago, you could get in whatever you liked.” He said he used to bring in explosives and foreign fighters for the Islamic State, also known as ISIS or ISIL. That allowed him to continue his regular business of smuggling food and other items, like cigarettes, into Syria. Now, he said, “the Turkish snipers shoot any moving object.”

At the coast, Turkey’s efforts to interdict more boats full of migrants came after the European Union agreed to pay Ankara more than $3 billion to help with education and health care for the refugees in the country.