Hundreds of demonstrators have gathered in the capital of Azerbaijan to protest against proposed constitutional changes that would extend the president's term.

Participants in the Saturday demonstration also carried portraits and placards in support of opposition activists who are jailed or under arrest. Azerbaijan has come under frequent criticism from human rights groups for repressing opposition.

The constitutional changes are to be voted on in a national referendum Sept. 26. They would extend the president's term to seven years from five and eliminate the minimum age for running for president. Opponents see the proposals as giving leverage to the governing establishment to establish long-term power.

Some critics characterize Azerbaijan as effectively a dynasty because President Ilham Aliyev is the son of the previous president.