BEIRUT (AP) — Syrian opposition activists say government troops are pushing deeper into an Islamic State stronghold in the country's east, the town of Mayadeen.

The Britain-based Syrian Observatory for Human Rights says clashes with militants intensified in the morning hours on Thursday in the town, as government forces advanced into the western and northern neighborhoods of Mayadeen, which lies on the Euphrates River.

The Observatory says troops were able to cut off the road linking Mayadeen and the town of Boukamal on the border with Iraq.

Opposition activist Mozahem al-Salloum says the fighting is fierce and that it will likely take time to rid Mayadeen of the Islamic State group.

Syrian troops reached Mayadeen on Saturday, after pushing south along the eastern banks of the Euphrates.