Damascus, May 22 (IANS): Islamic State (IS) militants have seized the last government-controlled border crossing between Syria and Iraq, a Syrian monitoring group said on Friday.

According to the Syrian Observatory for Human Rights (SOHR), the terror group seized the Syrian side of the al-Tanf -- known as al-Waleed in Iraq -- border-crossing on Thursday, following the withdrawal of Syrian troops, Xinhua news agency reported.

The IS capture of al-Tanf comes a day after the extremist group took full control over the ancient city of Palmyra in central Syria.

IS now controls "more than 95,000 sq km" of Syria, which is 50 percent of the country's entire territory, the SOHR said.

With the loss of al-Tanf to IS, the Syrian forces have lost all of their border crossings with Iraq, as the terror group had earlier captured the Bukamal crossing in Syria's eastern province of Deir al-Zour and Kurdish militants captured the al-Yarubiyeh crossings in the northeastern province of Hasakah.

Last month, the Syrian forces also lost the Nasib border crossing with Jordan to the Al Qaeda-linked Nusra Front.

The Syrian government currently has only two crossings with Lebanon, as the rest have fallen to various rebel groups in the north and east.