Israeli forces fired on two armed gunmen as they attempted to cross into the Golan Heights from Syria on Friday, the IDF said, reportedly killing both of them.

The suspects were trying to sabotage “operational infrastructure” along the border, a spokeswoman for the army said. Troops opened fire and confirmed hitting the two, she said.

The incident occurred near kibbutz Ein Zivan in the northern Golan.

The incident marked one of the most serious recent flare-ups at the Israel-Syrian border, which has become increasingly tense in the course of the ongoing Syrian civil war.

The troops opened fire in accordance with amended orders in the Syrian border area, which have been changed in recent days. Soldiers no longer initially seek to identify and warn infiltrators, but instead have been told to immediately fire on them, military sources have said in recent days, following a recent upsurge in cross-border incidents.

Earlier this month, an IDF soldier was badly injured and three others were also injured by a roadside bomb near the Syrian border.

That incident occurred outside the Druze town of Majdal Shams, after the soldiers apparently spotted a suspicious person near the border fence and approached to investigate.

The IAF retaliated for that incident by striking a Syrian army training facility, military headquarters and artillery batteries on Syria’s side of the Golan, which “aided and abetted” the roadside bombing. The Syrian army later said one of its soldiers was killed in the Israeli return fire.

Defense Minister Moshe Ya’alon issued a pointed warning to Syrian President Bashar Assad, whom he blamed for the attack.

“We won’t tolerate any breach of our sovereignty or attacks against our soldiers and civilians,” Ya’alon said. “We will react with might and resolve against anyone who acts against us, no matter where and when… Anyone who tries to attack us will be signing their own death sentence.”

The defense minister went on to declare that if the Syrian president “will continue to cooperate with terror elements that aspire to harm the State of Israel, we will continue to exact from him a heavy price in a manner that will make him regret his actions.”