Syrian President Bashar al-Assad has warned Israel that it will respond in kind to any future air strikes. Mr. Assad told a Lebanese TV channel a Russian contract to supply it with air defence missiles was being implemented – but did not confirm any deliveries. BBC reports that Israel has warned it will attack if the system is used against it. It has carried out strikes to stop weapons being sent to Hezbollah in Lebanon. Meanwhile heavy fighting continues in the strategic Syrian town of Qusair. A Syrian doctor has described the horrors of living there, telling the BBC that more than 600 injured people were trapped in rebel-held districts with no access to medical assistance. “They are waiting three to four days for drinking water and that doesn’t include the water they need for everyday use for washing their clothes and for normal day-to-day activities,” he said. There were women and children “dying in the battle for more control” of the town, which lies 30km (18 miles) south-west of Homs, he said. He said he had seen the bodies of “many” fighters from Hezbollah, the Lebanese Shia movement. Gen. Selim Idriss, the military chief of the main umbrella group of Syrian rebels, the Free Syrian Army, told the BBC on Wednesday that more than 7,000 Hezbollah fighters were taking part in attacks on Qusair. Meanwhile, United States and United Kingdom officials are looking into unconfirmed reports that an American woman and a British man have been killed in Syria. This follows a report aired by Syrian state TV showing the bodies and identity cards apparently of Westerners killed by government troops while fighting for the rebels in north-west Idlib province.