Updated

A Syrian activist group says the al-Qaida breakaway Islamic State of Iraq and the Levant has captured a key town near the Iraq border from other rebels.

The Britain-based Syrian Observatory for Human Rights says Boukamal fell to the militants Tuesday following days of battles.

The Observatory, which has a network of activists around Syria, said the group brought in reinforcements from Iraq during the fighting.

The latest victory by the jihadi group, which controls parts of Syria and Iraq, came two days after it declared the establishment of a transnational Islamic caliphate.

Last week, beleaguered fighters of the Nusra Front, al-Qaida's Syrian branch, defected and joined the Islamic State in Boukamal — effectively handing over the town to the powerful group, which controls the Iraqi side of the crossing.