Activists say Kurdish fighters and their allies have captured an Islamic State group military base in northern Syria.

The Britain-based Syrian Observatory for Human Rights and Kurdish activist Mustafa Bali said Kurdish fighters from the People's Protection Units, or YPG, captured the base known as Brigade 93 Monday night.

Bali and the Observatory said Tuesday that YPG fighters and their allies have entered parts of the nearby town of Ein Eissa, the last major residential area north of the extremists' de facto capital of Raqqa.

Last week, YPG fighters and allied rebel factions captured the Syrian town of Tal Abyad on the Turkish border, in a major setback for the Islamic State group.