An Azerbaijani court on Thursday jailed 26 men on terrorism-related charges in connection with an attack on a mosque in the capital Baku that killed two people, a court spokesman said.

The men received jail sentences of between two and 15 years on charges of terrorism, premeditated murder, forming an armed group and illegal weapons possession, the spokesman told AFP.

The group, dubbed the "Forest Brothers" in local media, included one Russian and two Turkish citizens, as well as 23 Azerbaijanis, the spokesman said.

The grenade attack on August 17 last year took place while the Abu-Bakr mosque, one of the most popular in Baku, was crammed with hundreds of worshippers. Six people were also injured.

The Abu-Bakr mosque is known for attracting conservative Muslims and has previously been linked by authorities with radical religious groups practicing Wahhabism -- a strict form of Sunni Islam.

The mosque has been closed since the attack despite pleas from its imam for it to be allowed to re-open.

Azerbaijan, a mainly Shiite Muslim country of 8.7 million on the Caspian Sea, has warned of a rising threat from Islamic militants, though critics allege it uses the spectre of extremism as a cover for persecuting political opponents.

An Azerbaijani court last month convicted two Lebanese men and four Azerbaijani citizens of plotting terrorist attacks on the Israeli and US embassies in Baku, sentencing them to between 12 and 15 years in prison.

Authorities earlier this year passed a law banning foreign citizens from leading prayers in Azerbaijani mosques and requiring leaders of religious organisations to be approved by the state.

Authorities said the changes were aimed at preventing Islamic extremism but rights groups alleged they are a violation of religious freedom.