DAMASCUS, Jan. 8 (Xinhua) -- An array of rebel groups unleashed an offensive Monday to reimpose a siege on a key military base in the eastern countryside of the capital Damascus, a monitor group reported.

The Levant Liberation Committee (LLC), previously known as the al-Qaida-linked Nusra Front, and allied militant groups waged intense battles to close the breach made by the Syrian army in the siege imposed on the Vehicle Management base in Harasta city in the Eastern Ghouta countryside of Damascus, the Syrian Observatory for Human Rights said.

The monitor group said if the rebels' offensive continued in the same momentum, the siege could be restored on that key base in Harasta.

The UK-based watchdog group said the battles in Harasta are coupled with intense airstrikes on areas in Eastern Ghouta, killing at 23 civilians and wounding tens of others on Monday.

Meanwhile, pro-government Sham FM radio cited military sources as saying that the army foiled the attack on the base on Monday.

It added that around 20 wounded soldiers were evacuated from the base to a military hospital in Damascus after the army broke the siege on Sunday night.

The ultra-radical rebels unleashed their offensive on the base late last month, succeeding to lay a siege on that big facility. The attack triggered a counter-offensive by the Syrian army, which was capped by breaking the siege.

The base is the largest military facility in the Eastern Ghouta region, stretching from Harasta to Arbeen area.

It hosts a large number of soldiers, including Republican Guards, as well as big weapon depots.

During the war, the base has become a major operation center and supply facility for the Syrian forces inside the Eastern Ghouta region, which has many towns and neighborhoods.