washington chairman u.s. house representatives intelligence committee say tuesday see evidence support president donald trump allegation wiretapped then-president barack obama 2016 presidential campaign republican representative devin nunes say trump assertion true leaders congress chairmen two intelligence committees know collectively gang eight brief see evidence nunes tell news conference think big question need answer whether mr. trump associate fact target intelligence agencies law enforcement authorities trump make accusation tweet saturday provide evidence obama spokesman deny trump since press house senate intelligence committees expand probe allegations russia meddle u.s. election look charge suppose keep speed pertinent counterintelligence investigation nunes say trump political campaign anybody associate trump type investigation clearly rise gang eight level adam schiff top committee democrat also say appear group appropriately brief schiff say scandal trump levy accusation obama say intelligence panel would address issue deal quickly nunes say committee plan public hear part russia probe begin one march 20 federal bureau investigation director jam comey admiral mike rogers director national security agency call testify former director national intelligence jam clapper former central intelligence agency director john brennan former act attorney general sally yates also invite nunes say panel would issue subpoena hear subpoena information pertinent investigation people either ... want appear appropriate agencies provide information ask for schiff address speculation issue partisan congress conduct credible investigation honest know yet say certain possible say news brief several hours nunes house intelligence chief see evidence back trump wiretap charge