At least two people were killed by a strike on one of the sites, the headquarters of a military unit southwest of Damascus, a war monitor said.

It was unable to confirm if the victims were civilian or military.

"Over the past few hours, the IDF (Israeli military) struck military targets in southern Syria including command centres and multiple sites containing weapons," the army said in a statement, without specifying the exact locations of the strikes.

"The presence of military forces and assets in the southern part of Syria pose a threat to the citizens of Israel. The IDF will continue to operate in order to remove any threat to the citizens of the State of Israel."

The Syrian Observatory for Human Rights said two military sites south of the Syrian capital were targeted, as AFP correspondents reported hearing loud explosions and warplanes flying over the city.

The observatory said "Israeli aircraft carried out four strikes on a military unit's headquarters southwest of Damascus. Simultaneously, another Israeli strike hit a military position in Daraa province".

The strike in Daraa province hit Tell al-Hara, a strategic hilltop overlooking large areas of the Golan and northern Israel, according to the observatory

-- 'Completely demilitarised' --

The latest strikes came after Netanyahu said on Sunday that southern Syria must be completely demilitarised, warning that Israel would not accept the presence of the forces of the new Syrian Islamist-led government near its territory.

"We will not allow forces from the HTS organisation or the new Syrian army to enter the area south of Damascus," Netanyahu said, referring to Islamist group Hayat Tahrir al-Sham which spearheaded the offensive that toppled Bashar al-Assad in December.

"We demand the complete demilitarisation of southern Syria, including the Quneitra, Daraa and Suwayda provinces," he said.

The same day Assad was ousted, Israel announced that its troops were entering a UN-patrolled buffer zone that has separated Israeli and Syrian forces on the strategic Golan Heights since 1974.

Israel seized much of the Golan Heights from Syria in a war in 1967, later annexing the area in a move largely unrecognised by the international community.

Netanyahu said that Israeli forces will remain in the buffer zone "for an indefinite period to protect our communities and thwart any threat".

Israel carried out hundreds of strikes in Syria during its civil war which broke out in 2011, mainly on Iranian-linked targets.

After the lightning offensive that ousted Syria's longtime president Assad, Israel carried out hundreds more air strikes on Syrian military assets in what it said was a bid to prevent them from falling into hostile hands.

Earlier on Tuesday, participants in Syria's national dialogue conference rejected what they said were "provocative" statements by Netanyahu.

In a closing statement, they also called on the international community to pressure Israel to stop any "aggression and violations", while condemning "the Israeli incursion into Syrian territory".