Two bombs exploded in the Algerian capital on Tuesday, killing 20 people and wounding 43, a security source said.
One blast killed 15 people near the Constitutional Court building and the other killed five close to the U.N. offices and a police station in the upscale Hydra district, the source said.
People ran through the streets in panic after the first blast and the wail of police sirens filled the air.
"I was nearby when I heard a huge explosion. I am fed up with this situation," student Mohamed Selnani told Reuters.
Telephone lines in the city of three million were jammed or not working, residents said.
Algeria is recovering from more than a decade of violence that began in 1992 when the then army-backed government scrapped elections a radical Islamic party was poised to win.
The violence has subsided since the 1990s but rebels aligned with Al Qaeda have carried out a string of attacks this year, including suicide bombings in the capital in April that killed 33 people.