BEIRUT (AP) " The Latest on the Syrian conflict (all times local):
Israeli defense officials say that Syrian President Bashar Assad still has up to three tons of chemical weapons.
The officials delivered the assessment on Wednesday, weeks after a chemical attack in Syria killed at least 90 people. Israel, along with much of the international community, believes that Assad's forces carried out the attack.
A senior military official says Israeli military intelligence estimates that Assad has "between one and three tons" of chemical weapons.
He spoke on condition of anonymity under military briefing rules. The assessment was confirmed by two other defense officials.
Assad has denied the allegations that he was behind the April 4 attack. Syria agreed to give up its chemical weapons arsenal in 2013.
The head of the international chemical weapons watchdog says laboratory tests have delivered "incontrovertible" evidence that three victims and seven survivors of a suspected April 4 chemical attack in Syria were exposed to sarin or a similar toxin.
Director-General Ahmet Uzumcu of the Organization for the Prohibition of Chemical Weapons said in a statement on Wednesday that the results "from four OPCW designated laboratories indicate exposure to sarin or a sarin-like substance."
He says further results will follow but that "the analytical results already obtained are incontrovertible."
The United States and many other nations have called the attack in the Khan Sheikhun area of Syria's southern Idlib province a chemical weapons attack and accused the Syrian government of responsibility.
The U.S. fired missiles at a Syrian army base it suspected of being the launching pad for the attack. Syria denies the charges.
An OPCW fact-finding mission is investigating the incident and is expected to issue a report within two weeks.
Britain's delegation to the chemical weapons watchdog says its director has told a meeting that tests indicate that sarin or a similar toxin was used in an April 4 attack in Syria that killed nearly 90 people.
In a tweet Wednesday, the U.K. delegation said Ahmet Uzumcu, the director-general of the Organization for the Prohibition of Chemical Weapons, made the statement at the opening of a closed-door meeting of the OPCW's executive council, which was discussing the attack.
Turkish and British tests also have concluded that sarin or a substance similar to the deadly nerve agent was used.
The United States blamed the chemical attack on the opposition-held town of Khan Sheikhoun on the government and fired nearly 60 missiles at a Syrian air base in response.
Syria's government denies the allegations.
The OPCW had no immediate comment.
Syrian state TV says the military is destroying a tunnel network that linked rebel-controlled towns which are being evacuated as part of a population transfer.
Government media said the area between Madaya and Zabadani came under military control Wednesday after gunmen and opposition activists were evacuated.
The evacuations from the two towns, and the northern pro-government villages of Foua and Kfarya, resumed Wednesday after being delayed by a bombing that killed more than 120 pro-government evacuees on Saturday.
Al-Ikhbariyah TV said medical aid and bread have been distributed to the residents of Madaya and nearby Baqeen. Images of starved children in besieged Madaya in late 2015 caused an international uproar but the government-imposed siege continued.
Critics say the string of evacuations, which could see some 30,000 people moved across battle lines over 60 days, rewards siege tactics and amounts to forced displacement along political and sectarian lines.
Syrian state TV says an explosive device has gone off in the northern city of Aleppo, killing six people and wounding others.
It did not provide further details on Wednesday's blast in the government-held Salaheddin neighborhood. Opposition media groups, including Aleppo Today, say the explosion occurred near a mosque during the funeral of government fighter.
Aleppo was divided between government and rebel-held districts for years, but government forces managed to drive rebels from the city in December with a Russian-backed offensive. Some contested areas remain.
Syria's military media says the evacuation and transfer of thousands of Syrians from four besieged areas has resumed.
The reciprocal evacuations from two pro-government villages and two opposition-held towns was disrupted by a bombing Saturday that killed more than 120 pro-government evacuees, mostly children.
The Central Military Media says 3,000 residents of the pro-government villages, Foua and Kfarya, left Wednesday in 45 buses bound for government-controlled Aleppo.
Another 11 buses carrying opposition fighters left Madaya and Zabadani, near Damascus, heading toward the northern rebel-held Idlib province.
The opposition-run Syrian Observatory for Human Rights also reported the transfer, which it says includes 800 armed men from both sides.
The population exchange has been criticized by rights groups, which say it rewards siege tactics and amounts to forcible displacement.