He described the allegations as still being reviewed as part of an extensive background check process that Porter was still in the midst of when reports made the charges public this week.
Asked what caused the White House to change its tone on Porter, Shah replied the images of one of Porter's ex-wives' black eye were "upsetting."
He declined to say whether Kelly knew about the allegations long before the reports were published.
Trump's defense of the alleged wife abuser comes after he encouraged "lock her up" chants about 2016 Democratic presidential nominee Hillary Clinton over her use of a personal server while secretary of state. He also has called on other political foes and some of those looking into potential collusion between his 2016 campaign and Russia to be the subject of federal probes and possible prosecution.
The president did not comment on the fate of his embattled chief of staff. Some women's organizations, for instance, have called on Kelly to step down for reportedly knowing about the Porter allegations for months but keeping him on staff -- even allowing him to become his right-hand man.
Kelly's repeated defenses of Porter earlier this week and his allowing Communications Director Hope Hicks, Porter's current girlfriend, to craft a number of Thursday statements about the matter has again made the chief of staff a lightning rod for Democrats. (He has caught their ire also over his hard-line comments about illegal immigrants.)
For instance, Democratic Rep. Pramila Jayapal of Washington called Kelly's role in keeping Porter on as a White House staffer even after learning of the allegations "very, very disturbing."
"Clearly, WH Chief of Staff John Kelly knew about Rob Porter's history of abuse directly from FBI and chose to ignore it," Jayapal tweeted Thursday morning. "#MeToo is as much about those who protect the abusers with their silence as the abusers themselves."
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