Jordanian civilians living near the border with Syria reported heavy clashes between the Jordanian and Syrian armies late Saturday night, during which the Syrian army allegedly crossed the border and used attack helicopters.

Residents of Ramtha, located 2 miles from the Syrian border, told the Islamist Jordanian daily As-Sabeel that they flocked to their rooftops to view the heavy exchange of fire near the Ramtha border crossing around midnight Sunday morning. No report of military clashes appeared in the Jordanian mainstream media.

One Syrian shell landed near a mosque in Ramtha, Qatari news channel Al-Jazeera reported on Sunday, causing Jordanian tanks stationed at the border to return fire towards Syria. Al-Jazeera reported a state of panic among Jordanian residents of the border area, some of whom left their homes after the shelling shattered their windows.

Syrian opposition activists told Al-Jazeera that heavy clashes are raging between forces loyal to President Bashar Assad and the Free Syrian Army in the southern Syrian city of Daraa. As-Sabeel speculated that the shelling — described as the most significant border incident since the start of the Syrian revolution in March 2011 — was the result of massive defections from the Syrian Army, which the government was attempting to curb.

Residents of southern Syria have fled southward across the Jordanian border to escape the violent uprising that has plagued the country for 21 months. Nearly 500,000 Syrians have already found refuge in neighboring Jordan.

A Jordanian soldier was killed at the border on October 22 while trying to prevent militants from infiltrating into Syria. In August, a Jordanian soldier was injured while assisting Syrian refugees fleeing the regime to enter Jordan.