TEHRAN, Jan. 12 (Xinhua) -- Iran's Foreign Ministry on Sunday summoned Robert Macaire, the British ambassador to Iran, for what it called the envoy's "unusual behavior" and "attending an illegal gathering" in Tehran.

"Iran handed over its formal protest to Macaire and the British government," the ministry's website said.

The British ambassador was reminded that "participation of foreign ambassadors in illegal gatherings do not correspond to their responsibilities as the political representatives of their respective countries," according to the ministry's report.

Iranian officials detained Macaire on Saturday amid an anti-government gathering outside of a university in Tehran. He was released about an hour later.