JERUSALEM (AP) — The Israeli military said it thwarted an infiltration attempt from Syria early on Monday staged by four suspected militants it accused of trying to plant explosives.

Lt. Col. Jonathan Conricus, a military spokesman, said Israeli troops earlier spotted “irregular” activity in the Golan Heights. Israeli troops opened fire on the suspected militants, some of whom were armed, after observing them placing the explosives on the ground, Conricus said.

There was no official confirmation that the four suspected attackers were killed but a grainy video released by the army shows four figures walking away from barbed wire marking the frontier. The four then disappear in a large explosion that engulfs the area.

The Israeli military has not said if the four are suspected of ties to Iran or Hezbollah, two Syrian allies. However, Conricus said Israel held the Syrian government responsible for the incident.

Addressing Likud party lawmakers, Prime Minister Benjamin Netanyahu said on Monday that Israel "thwarted an attempted sabotage on the Syrian front” and would continue to “harm all those who try to harm us and all those who harm us.”

Syria's state-run SANA news agency did not immediately acknowledge the Israeli strike.

Israel captured the Golan Heights from Syria in 1967 and later annexed the territory. The U.S. is the only country to have recognized Israel’s annexation.

The incident comes amid heightened tension on Israel's northern frontier following a recent Israeli airstrike that killed a Hezbollah fighter in Syria. Following the airstrike, the Israeli-controlled Golan Heights was hit by explosives fired from Syria and Israel responded by attacking Syrian military positions and beefing up its forces in the area.

Israel has been bracing for further retaliation and last week it said it thwarted an infiltration attempt from Lebanon by Hezbollah militants, setting off one of the heaviest exchanges of fire along the volatile Israel-Lebanon frontier since a 2006 war between the bitter enemies.

Israel considers Hezbollah to be its toughest and most immediate threat. Since battling Israel to a stalemate during a monthlong war in 2006, Hezbollah has gained more battlefield experience fighting alongside the Syrian government in that country's bloody civil war.

After 40 years of calm, the Israel-Syrian frontier has heated up in recent years as Iran has tried to establish a military foothold on Israel's doorstep while helping Syrian President Bashar Assad in his country's yearslong war. Hezbollah also has aided Assad.