Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. Last-ditch Attempt Seen for Syria Cease-fire Pact by Steve Herman STATE DEPARTMENT -- Intensive diplomatic efforts have resumed in Europe in what some observers see as a last-ditch effort to bring about a cease-fire in Syria. A key focus is an attempt by American and Russian negotiators, who have been meeting on and off for weeks, to resolve what are described as technical sticking points. U.S. diplomats, speaking to VOA News, have expressed frustration with their Russian counterparts whom they have accused of reversing direction on some key points of agreement in recent days. "Today's news out of Syria is not encouraging," U.S. Defense Secretary Ash Carter said Wednesday in a speech at Oxford University in England. "The choice is Russia's to make, and the consequences will be its responsibility." FILE - Defense Secretary Ash Carter opens the Global Coalition to Counter IS Meeting at Joint Base Andrews, Maryland, outside of Washington, D.C., July 20, 2016. Carter accused Moscow of "unprofessional behavior" in Syria, Ukraine and cyberspace, alleging the Russians have a clear ambition to erode the principled international order." Negotiations continue U.S. Secretary of State John Kerry and Russia's Foreign Minister Sergei Lavrov "plan to meet in the coming days to see if they can conclude an agreement, having now identified the remaining issues," said Ben Rhodes, deputy national security advisor for strategic communications, traveling with President Barack Obama in Laos. "We're not going to take a deal that doesn't meet our basic objectives," Rhodes told reporters. "And I think we'll know very quickly whether or not we can close those remaining gaps." Even if the American and Russian diplomats bridge those gaps it might not prove palatable to some of the elements fighting in Syria. "If what the Russians and the Americans agree upon is very much different from what the Syrians aspire to, then we shall not accept it," said Riyad Hijab, the top coordinator for the main Syrian opposition negotiating group at stalled U.N.-mediated talks in London. A key sticking point involves the fate of Syrian President Bashar al-Assad, whom the opposition groups insist must leave office at the end of six months of negotiations to establish a transitional administration. Russian President Vladimir Putin (R) shakes hands with Syrian President Bashar al-Assad during a meeting at the Kremlin in Moscow, Russia, October 20, 2015. "It's not a question of keeping Assad in for six months or one month or one day, in this transitional period. The Russians and Americans know that," said Hijab. "They know the position of the Syrian people, they have sacrificed a lot and they will not give up this demand." A proposed Syrian cease-fire was discussed on Monday during a 90-minute meeting between Obama and Russian President Vladimir Putin on the sidelines of the G-20 Summit in Hangzhou, China. Russia, along with Iran, supports Assad. Adel al-Jubeir, the foreign minister of Saudi Arabia, the primary rival of Iran, said Tuesday in London a cease-fire accord was possible within 24 hours, but cautioned that Assad is unlikely to abide by any agreement. Military Complications Meanwhile, an Iraqi Shiite militia (Harakat al-Nujaba), allied with Syria's army and fighting Islamist rebels, on Wednesday claimed it had dispatched 1,000 additional fighters to the southern part of besieged Aleppo. Aleppo was the target of an apparent chlorine attack on Tuesday. Monitors quote civilians saying that more than 100 people took ill after a missile was fired by a Syrian jet. Turkish officials said Wednesday that about 300 Syrian civilians were returning home to Jarablus following a Turkish-backed incursion into northern Syria. A soldier gestures as Turkish Army tanks drive to the Syrian-Turkish border town of Jarablus, Aug. 25, 2016 Turkey should refrain from taking deeper steps into Syria, said Russia's foreign ministry in a statement issued Wednesday, arguing Ankara's actions call into question Syrian sovereignty and territorial integrity. A complex war has been raging in Syria for five years, fracturing the country, killing hundreds of thousands of people and displacing 12 million, more than half of the country's pre-war population. An additional 100,000 people were forced to flee by fighting in the Hama Governorate (province) between August 28 and September 5, according to the United Nations.