Iranian officials said the envoy, Mohammad B. Bahrami, was summoned to Tehran to discuss recent protests outside the Iranian Embassy in Baku, in which demonstrators were said to have insulted symbols of Islam. Mr. Bahrami left on Monday.

"He was recalled for consultations," an embassy official, Ahmed Nemati, said in a statement. This month three protests were held outside the embassy. Some demonstrators carried pictures of the Iranian supreme leader, Ayatollah Ali Khamenei, including one that showed him with a bare midriff.

In recent months, relations have grown increasingly tense between Azerbaijan, an oil-rich former Soviet republic on the Caspian Sea, and Iran, its southern neighbor.

Iran is under severe pressure by the United States and other Western nations over its nuclear program and facing a new round of economic sanctions. Tehran has complained of Azerbaijan's improving relationship with Israel, which has included purchasing Israeli-made weapons, and Azerbaijan has denied reports that it had agreed to let Israel use military bases on its territory for a possible airstrike on Iran.

Azerbaijan, meanwhile, has accused Iran of plotting terrorist attacks in Baku. Earlier this year, Azerbaijan arrested 22 people and accused them of being terrorist agents working for Iran.

The diplomatic squabble unfolded as Azerbaijan is playing host this week to the hugely popular Eurovision Song Contest. The television spectacle has attracted visitors from around the world, including many Iranians. A spokesman for the Azerbaijan Foreign Ministry, Elman Abdullayev, suggested envy was a factor in the recall of the ambassador.

"Unfortunately, the development of Azerbaijan, holding such a grand event as Eurovision, the arrival of many guests here, are perceived by some with jealousy," Mr. Abdullayev said.

Azerbaijan has complained about Iranian jabs at Eurovision in recent weeks, including rumors on some Iranian Web sites that a gay pride march would be held in Baku during Eurovision. Azerbaijan is a mostly Muslim country but has a secular government, while Iran is an Islamic theocracy.

The picketing outside the Iranian Embassy in Baku was apparently a response to anti-Azerbaijan demonstrations in Tehran.