BEIRUT — Rebels attacked a major Syrian army base in the southern province of Daraa on Tuesday in the latest push by opposition fighters against President Bashar Assad’s embattled forces, activists said.

Assad’s forces have suffered several defeats over the past three months at the hands of insurgents, members of al-Qaida’s branch in Syria and the Islamic State extremist group. The government lost the northern city of Idlib, the central historic town of Palmyra and a southern border crossing point with Jordan.

The Western-backed Free Syrian Army rebel group launched the assault at dawn on the army base, known as Brigade 52, said Ahmad al-Masalmeh, an opposition activist in Daraa. He said the rebels have captured the nearby village of Mleiha al-Sharqiyeh.