An honorary consul of Syria in the United States resigned on Wednesday in protest over the killing of more than 100 civilians in the Syrian town of Houla over the weekend that has drawn widespread international condemnation.Hazem Chehabi, a US citizen and a businessman based in Orange County, had held the California post for nearly 20 years, working on passports and other matters, and had been at the center of a pressure campaign in recent months over his ties to the Syrian government."You get to a point where your silence or your inaction becomes ethically and morally unacceptable," Chehabi, Syria's Honorary Consul General in California, told NPR's Morning Edition."The recent barbaric massacre that took place in the town of Houla, for me it was a tipping point and was a point beyond which one could not justify remaining silent and/or remaining in a position that may be perceived, correctly or incorrectly, as having ties to the Syrian government," he added, according to a transcript of the remarks.Chehabi's resignation followed a US move to expel Syria's top diplomat in Washington on Tuesday after what it described as the "despicable" massacre."His family, including his father, are a very well-known part of the establishment," Ammar Kahf, a spokesman for the activist group Syrian-American Council, told Reuters. "He was known to have a close relationship with (Syrian President) Bashar Assad."Chehabi's father, General Hikmat Chehabi, was the army chief of staff under Assad's late father, Hafez al-Assad, Kahf told Reuters.Chehabi, a doctor, received his M.D. from the University of Damascus Medical School, according to a biography on the website for of the Newport Diagnostic Center, a medical outpatient center he formed in Orange County. He is also the chair of the University of California, Irvine Foundation, and once served as president of the American College of Nuclear Physicians.In recent months he was at the center of a controversy over his ties with the Assad government. In March the UC Irvine student government called for his removal from the Board of Trustees.That motion was seconded in April by a coalition of advocacy groups including the Muslim Public Affairs Council and the Los Angeles chapter of the Council on American-Islamic Relations.Chehabi did not respond to phone inquiries for comment. Nor did the storefront consular office that serves the large Syrian-American community in Southern California.