Israel carried out a wave of heavy airstrikes across Syria as its troops advanced deeper into the country, a Syrian opposition war monitor said Tuesday, and the Israeli defense minister announced that his forces had destroyed Syria’s navy.

Israel acknowledged pushing into a buffer zone inside Syria following the overthrow of President Bashar Assad. But it remained unclear if its soldiers had gone beyond that area, which was established more than 50 years ago. Israel denied that it was advancing on the Syrian capital of Damascus.

Israeli officials have said they are striking military targets, including heavy weapons, suspected chemical weapons sites and air-defense systems, to prevent them from falling into the hands of extremists. Photographs circulating online showed destroyed missile launchers, helicopters and warplanes. Associated Press reporters in the capital heard heavy airstrikes overnight and into Tuesday morning.

Israeli Defense Minister Israel Katz said Israel intended to establish a demilitarized zone in southern Syria.

Speaking at a navy base in Haifa, Katz said the army will create “defense zone free of weapons and terrorist threats in southern Syria, without a permanent Israeli presence, in order to prevent terrorism in Syria from taking root.”

He gave few details on what that entailed, but warned Syria’s rebels that “whoever follows Assad’s path will end up like Assad. We will not allow an extremist Islamic terrorist entity to act against Israel.”

In an area where so many geopolitical lines are packed closely together, any military movement can spark regional fears. It is barely 25 miles (60 kilometers) from Damascus to the buffer zone, and only a few more miles to Israeli territory.

There was no immediate comment from the insurgent groups — led by Hayat Tahrir al-Sham, or HTS – that have taken control of much of the country. Their lightning advance brought an end to the Assad family’s half-century rule after nearly 14 years of civil war, leaving many questions about what comes next.

Members of the ousted Syrian government will gradually transfer power to a new transitional cabinet headed by Mohammed al-Bashir, who reportedly headed the rebel's “salvation government” in its southwest Syrian stronghold.

Outgoing officials met for the first time Tuesday with al-Bashir, who told reporters that the transitional period would last until the beginning of March.

Life in the capital is slowly returning to normal after the overthrow of Assad, who fled the country over the weekend and has been granted political asylum in Russia.

Private banks reopened on instructions from the central bank, said Sadi Ahmad, who runs a branch in the upscale Abu Rummaneh neighborhood. He said all his employees returned to work.

Shops also reopened in the city's ancient Hamidiyeh market, where armed men and civilians could be seen buying perfume and ice cream. A clothing shop owner, who asked not to be named for fear of retribution, said he hoped vendors would no longer have to pay bribes to security officials.

At Bakdash, a famous ice cream shop, a poster outside read: “Welcome to the rebels of free Syria. Long live free Syria.”

“Damascus is more beautiful now," said Maysoun Qurabi, who was shopping in the market. “It has a soul, and people feel at ease and secure.” Under Assad, she said, “people were hungry and scared. The regime was strong."

In the immediate aftermath of Assad's fall, Israeli forces moved into a roughly 400-square-kilometer (155-square-mile) buffer zone inside Syria that was established after the 1973 Mideast war, a move it said was taken to prevent attacks on its citizens.

Israel has a long history of seizing territory during wars with its neighbors and occupying it indefinitely, citing security concerns. Israel captured the Golan Heights from Syria in the 1967 Mideast war and annexed it in a move not recognized internationally, except by the United States.

The Britain-based Syrian Observatory for Human Rights, which has closely tracked the conflict since the civil war erupted in 2011, said Israel has carried out more than 300 airstrikes across the country since the rebels overthrew Assad.

The Observatory, and Beirut-based Mayadeen TV, which has reporters in Syria, said Israeli troops are advancing up the Syrian side of the border with Lebanon and had come within 25 kilometers (15 miles) of Damascus, which the Israeli military denied.

Lt. Col. Nadav Shoshani, an Israeli military spokesperson, said “reports circulating in the media about the alleged advancement of Israeli tanks towards Damascus are false.” He said Israeli troops are stationed within the buffer zone in order to protect Israel.

Israel's military had previously said troops would enter the buffer zone “and several other places necessary for its defense.”

Israeli media, meanwhile, reported that the air force was methodically destroying Syria's military assets to ensure whoever rules the country next would have to rebuild them.

The operations “have been systematically destroying all that remains of the escaped tyrant’s military,” wrote Yossi Yehoshua, the military correspondent for Israel's largest daily, Yediot Ahronot.

“Dozens upon dozens of targets, including arms depots of various kinds, have been hit in waves of attacks so as to prevent them from falling into hostile hands and from posing a threat to Israel." The air force “currently enjoys complete freedom of action,” he added.

Israeli Prime Minister Benjamin Netanyahu later confirmed the airstrikes, saying they aimed to destroy the toppled government’s leftover “military capabilities,” and said Israel wants relations with the new government in Syria. He spoke in a video statement recorded after his first day of testimony in his corruption trial.

Egypt, Jordan and Saudi Arabia have condemned Israel’s incursion, accusing it of exploiting the disarray in Syria and violating international law.

Turkey, which has been a main backer of the Syrian opposition to Assad, also condemned Israel’s advance. The Turkish Foreign Ministry accused Israel of“displaying a mentality of an occupier” at a time when the possibility of peace and stability had emerged in Syria.

U.N. spokesman Stephane Dujarric on Monday said Israel's incursion constitutes a violation of the 1974 disengagement agreement and called on both Israel and Syria to uphold it.