ATHENS — Time and again, when President Recep Tayyip Erdogan of Turkey wants something from the Europeans, he has reminded them that he is the gatekeeper to tens of thousands of refugees he could send their way.

Friday was much the same, as Turkey demanded help from NATO after a deadly clash in Syria. But this time, Mr. Erdogan not only threatened to let refugees enter Greece. Local officials bought several thousands of them tickets, helped them onto shiny Mercedes-Benz buses and drove them to the border.

The mini-exodus was accompanied step by step by state-run Turkish media, which live-streamed scenes of harried families pushing off shore for Greek islands in scenes reminiscent of the 2015 migrant crisis that Europe was able to solve only with Turkish help.

The echoes of that crisis were no doubt deliberate on the part of Mr. Erdogan, who knew he could count on the desperation of refugees eager to make their way to Europe to make his point. Friday’s events were widely seen as his attempt to weaponize both the desperation of migrants and the xenophobia of Europe.It was the ninth time, in fact, that the Turkish president has promised to send a new surge of refugees Europe’s way. Whether Mr. Erdogan was merely dangling the threat again, or will unleash a full-blown crisis remains to be seen.