Syrian government forces close in on last Islamic State (IS) key stronghold in al-Bukamal. (Xinhua Photo)

DAMASCUS, Oct. 25 (Xinhua) -- The Syrian government forces are advancing in the countryside of Deir al-Zour province in eastern Syria in fighting the Islamic State (IS) in al-Bukamal, the last major IS stronghold near the Iraqi border, a military source told Xinhua on Wednesday.

The Syrian troops are now fighting to retake the T2 oilfield all the way to reach al-Bukamal, just days after the government forces dislodged IS from the city of al-Mayadeen, which was deemed as the IS' capital in Deir al-Zour, the source told Xinhua on condition of anonymity.

The Syrian Observatory for Human Rights monitor group also reported the progress of the Syrian army, saying the troops are advancing toward al-Bukamal under heavy cover of shelling.

Al-Bukamal is very important for IS due to its proximity to IS-held areas on the Iraqi side of the border.

Meanwhile, the Iraqi Hashid Shaabi, or the Popular Mobilization Forces, are bracing to eliminate IS in the areas they control on the Iraqi side of the border in tandem with the Syrian military operations against al-Bukamal.

The operation seemed coordinated between the Syrian and Iraqi forces in the border region to clear it completely from IS.

In the capital city of Deir al-Zour, the Syrian army captured the al-Sina' neighborhood from IS, as activists said the government troops are now controlling over 90 percent of Deir al-Zour city as a result of the weeks-long offensive in that key area.

Politically, the Riyadh-backed Syrian opposition groups will convene in the Saudi capital next month in a bid to reach an agreement to unify the opposition delegation to the upcoming intra-Syrian talks in Geneva.

Uniting the opposition delegations in one is a demand of Russia, which said that the Geneva talks won't take place if the Syrian opposition groups didn't unite in one delegation.