New Yor - Merck chief executive Kenneth Frazier, who is African American, resigned on Monday from a White House advisory panel on manufacturing, calling the decision a "matter of personal conscience" following President Donald Trump's initial response to a violent white supremacist rally."America's leaders must honor our fundamental values by clearly rejecting expressions of hatred, bigotry and group supremacy, which run counter to the American ideal that all men are created equal," Frazier wrote on Twitter."As CEO of Merck and as a matter of personal conscience, I feel a responsibility to take a stand against intolerance and extremism."Trump, also on Twitter, responded about an hour later."Now that Ken Frazier of Merck Pharma has resigned from President's Manufacturing Council, he will have more time to LOWER RIPOFF DRUG PRICES!" the US president said.Frazier announced the decision on Monday morning as criticism mounted of Trump's failure over the weekend to explicitly denounce the neo-Nazis and Ku Klux Klan members whose rally in Charlottesville, Virginia set off violent clashes that culminated when a man drove his car into a crowd of counter-protesters, killing a young woman and injuring 19.Two state police officers responding to the events died in a helicopter crash near the area.Later on Monday, Trump made a statement calling out specific hate groups."Racism is evil. And those who cause violence in its name are criminals and thugs, including the KKK, neo-Nazis, white supremacists and other hate groups that are repugnant to everything we hold dear as Americans," he said from the White House.The Justice Department has launched a civil rights inquiry into the incident, and the driver, a 20-year-old Ohio man who was said to have had a history of neo-Nazi beliefs, has been charged with second-degree murder.Frazier is a Harvard Law School-trained attorney whose experience includes pro bono work that won the release of a wrongly convicted death row inmate in Alabama. Frazier is not the first executive to depart a Trump advisory panel. After Trump announced he would withdraw the United States from the Paris climate agreement, Disney chief executive Bob Iger and Tesla Motors head Elon Musk both left a White House advisory council, joining former Uber leader, who stepped down in February following criticism of Trump's travel ban.But most other executives appear to be staying put. "Heartbroken by the violence in #Charlottesville. Hate and intolerance are a betrayal of what we stand for as Americans," said Pepsi chief executive Indra Nooyi on Twitter, in a statement that did not address the Trump panel.Other executives, including those from General Electric and Dow, planned to stay on Trump panels, US financial news media reported on Monday.