Damascus - Syria's foreign ministry on Sunday denounced accusations the government had deployed chemical weapons against a rebel-held town as an "unconvincing broken record".Damascus has been accused of perpetrating a toxic gas attack late on Saturday that left dozens dead and many more suffering breathing problems in Douma. "Allegations of chemical use have become an unconvincing broken record, except for some countries that trade with the blood of civilians and support terrorism in Syria," state news agency SANA quoted a ministry source as saying. "Every time the Syrian Arab Army advances in the fight against terrorism, allegations of chemical use are used as an excuse to prolong the life of terrorists in Douma," it said. Douma is the last rebel-held town in Eastern Ghouta, once the opposition's main bastion near Damascus but now battered by a seven-week regime assault. The offensive has recaptured 95 percent of Ghouta, and the government announced on Sunday that it had reached a deal for rebels to be evacuated from their last holdout in Douma.