The U.S. representative on a committee overseeing the ceasefire agreement that ended the latest Israel-Hezbollah war said Friday that “significant progress” had been made ahead of a looming deadline to implement all the terms of the deal.

However, Maj. Gen. Jasper Jeffers' statement appeared to leave some ambiguity on whether Israel would withdraw its forces from all of southern Lebanon by the ceasefire's Feb. 18 deadline, saying only that he was confident “all population centers in the Southern Litani Area” would be back under Lebanese control by then.

In a speech to a crowd of supporters at his father's tomb on Friday, ex-PM Saad Hariri stopped short of announcing a return to politics, but did say his al-Mustaqbal Movement would "stay with you and be your voice in all national milestones and in all upcoming events."

Thousands of supporters gathered in downtown Beirut Friday to commemorate the 20th anniversary of former Prime Minister Rafik Hariri's assassination, which comes amid seismic regional political shifts.

The ousting of Bashar Assad in December after 54 years of family rule in Syria marked the fall of a government long accused of orchestrating Hariri's assassination and other political killings in Lebanon.

In a desolate area of Syria where Lebanese militant group Hezbollah once held sway, security forces shot open the gates to an abandoned building and found a defunct drug factory.

Syria's new authorities launched a security campaign last week around Qusayr at the porous Lebanese border, cracking down on drug and weapons smugglers.

The Israeli military is prepared to withdraw from Lebanese territory and hand over areas to the Lebanese Army "within the timeline" set by a U.S.-French-mediated ceasefire agreement, a senior Israeli security official said.

Israeli fighter jets overnight hit what the Israeli army said were Hezbollah military sites "containing weapons and launchers, which pose a direct threat to the Israeli home front."

Lebanese media reported that Israeli aircraft had targeted sites near the town of Yater. Warplanes were also seen flying over southern Lebanese villages and towns.

U.N. Secretary-General Antonio Guterres' deputy spokesman Farhan Haq said "we continue to urge Israel and Lebanon to honor their commitments to the cessation of hostilities understanding."

"Continued progress in Lebanese Armed Forces redeployment and Israeli Defense Force withdrawal is crucial," Haq said, adding that "the parties must avoid any action that could raise tensions, endanger civilians and further delay their return to their towns and villages on both sides."

Lebanon on Friday marks 20 years since former prime minister Rafik Hariri's assassination amid seismic political changes that have weakened Hezbollah and its backers and could herald a comeback for Hariri's son Saad.

Rafik Hariri, a towering political figure, had resigned as premier when a suicide bombing targeted his convoy in Beirut, killing him and 21 others on February 14, 2005.

Hezbollah supporters blocked the Beirut airport road and burned tires on Thursday to protest a decision barring two Iranian planes from landing in the Lebanese capital, state media and an airport official said.

"Young men set tires on fire in front of the airport entrance, raising banners supporting Hezbollah's former Secretary-General Sayyed Hassan Nasrallah," said Lebanon's National News Agency (NNA).

Speaker Nabih Berri said on Thursday that Lebanon rejected Israel's demand to remain in five locations in the south after the deadline for fully implementing a ceasefire deal next week.

The United States, a key mediator, "informed me that the Israeli occupation will withdraw from villages it still occupies on February 18, but it will remain in five points," Hezbollah ally Berri said.