The U.S. Justice Department has named a special counselto investigate whether Russia and Donald Trump's campaignworked together to influence the 2016 presidential election.The Justice Department said in a statement Wednesday thatformer FBI Director Robert Mueller will oversee the investigation of"Russian government efforts to influence the 2016 election and related matters."Trump said Wednesday the independent investigation will show, in his words,"there was no collusion between my campaign and any foreign entity."Deputy Attorney General Rod Rosenstein made the appointment.He said, "I have determined that a special counsel is necessaryin order for the American peopleto have full confidence in the outcome" of the investigation.Mueller served as FBI director under both Republican and Democratic presidents.He led the agency from 2001 to 2013, before ousted director James Comey.President Trump fired Comey last week.A small but growing number of Republican lawmakers have joined Democratsin calling for an independent investigation into possible tiesbetween Russia and Trump's 2016 presidential campaign.Reaction from both Republican and Democratic lawmakersabout Mueller's appointment was positive.Mueller's investigation would be separatefrom the ongoing investigations by the FBI and several Congressional committees.The calls for an independent and non-political appointmenthave grown following Comey's dismissal.And news reports Tuesday said that Comey wrote a memodescribing a meeting he had with President Trump in February.In the memo, Comey reportedly wrote that Trump asked him to stopthe investigation of former National Security Adviser Michael Flynn's ties to Russia.Three Republican-led congressional committees have saidthey want Comey to answer questions about the memo.Lawmakers also want the FBI to hand over any notes that Comey leftabout discussions he had with White House officials on the Russia investigation.Congressional investigators are also asking for documentsfrom the Justice Department related to the firing.Stocks fell sharply on Wall Street Wednesday,as investors worried about how the latest problems in Washingtoncould affect Trump's plans for the economy.