BEIRUT: Syrian President Bashar al-Assad on Saturday announced an amnesty for men at home and abroad who have dodged conscription, to help bolster the ranks of an army severely depleted by four years of battling armed insurgents.

The decree, announced on state television, pardons those who violated Syria's conscription law, an offense punishable by imprisonment and sometimes death. It underscores the government's difficulty in mobilising men to help fight a protracted war in the face of a bloody insurgency.

The Syrian Observatory for Human Rights, a monitor that tracks violence, puts the number of draft dodgers at 70,000. The decree gives one month for those inside Syria and two months for those abroad to turn themselves into authorities.

The Syrian army, one of the region's largest, has been over stretched by a four-year civil war where it is battling on several major fronts Islamist rebels and ultra-hardline jihadist militants who have seized large swathes of territory. Many young men have fled the country or found ways to avoid conscription.

Although defence experts say the amnesty could encourage the draft dodgers to enlist, others say it may not be enough to attract young men opposed to the war.

The regular army's numbers have shrunk sharply to 200,000 from 350,000 before the crisis, according to the Observatory.

The army has become increasingly reliant on pro-government militias recruited in state-controlled provinces that are offered lucrative pay to fight alongside the regular army.

At least 80,000 Syrian army soldiers and officers had been killed since the conflict began, according to the Observatory.

The army has been forced in recent months to withdraw from large parts of the northwestern province of Idlib in the face of an assault by a coalition of Islamist brigades and was unable to defend the desert city of Palmyra in central Syria, when it was overrun by Islamic State.

Some diplomats say the army now focuses on defending strategic areas such as Damascus, Homs and strongholds of Assad's minority Alawite sect in coastal areas.

With no end in sight to the war, the Syrian army's manpower shortages have been underlined in recent months by a growing reliance on foreign fighters.

Iranian military support for Assad has come in the form of backing for the Lebanese Shi'ite militant group Hezbollah, which is fighting alongside Assad's forces in the war, the deployment of Iranian military advisers and the mobilisation of Shi'ite fighters from elsewhere in the Middle East

Syria's war has killed close to a quarter of a million people and driven millions more from their homes in one of the worst global refugee crises since World War Two.