Trump had refused to rule out a third-party run during the Aug. 6 Republican debate.
NEW YORK -- Donald Trump will sign a pledge to back the Republican presidential nominee and not to run as an independent should he not win the party's nomination, multiple outlets have reported.
14:29 Donald Trump’s Answer to a Question About Women’s Issues Is to Put Ivanka on the Phone4
15:40 Russia's Putin calls Donald Trump 'a clever man' who will learn18
23:30 Trump breaks US stance with direct Taiwan call13
18:46 Obama expected to sign Iran Sanctions Act extension into law: White House13