Two provocative incidents in Stockholm this month have energized Turkish President Recep Tayyip Erdogan ahead of tight elections and dimmed Sweden and Finland's hopes of joining NATO before the summer, diplomats, analysts and opposition politicians say.

Erdogan was quick to thrust the issue of NATO expansion into domestic politics after a copy of the Muslim holy book, the Quran, was burned at the weekend, and an effigy of the Turkish leader was strung from a lamppost a week earlier.

The incidents, while not illegal in Sweden, hobbled Stockholm's effort to win Ankara's support for its bid to join U.S.-led NATO, which Sweden made last May alongside Finland in the face of Russia's invasion of Ukraine.