Murphy: Immigration surge began under Trump

An ally of President BidenJoe BidenEx-Biden adviser says Birx told him she hoped election turned out 'a certain way' Cheney rips Arizona election audit: 'It is an effort to subvert democracy' News leaders deal with the post-Trump era MORE argued Sunday that U.S. policy was not the primary driving factor behind a surge of migrants at the U.S.-Mexico border, instead blaming longstanding conditions in Central America and the desperation of migrants.

Sen. Chris MurphyChristopher (Chris) Scott MurphyAntsy Democrats warn of infrastructure time crunch 'The era of bipartisanship is over': Senate hits rough patch Senate gun background check talks hit wall MORE (D-Conn.) told "Fox News Sunday" host Chris WallaceChristopher (Chris) WallaceLewandowski says Trump has not spoken to him about being reinstated Divisions remain on infrastructure as clock ticks on bipartisan deal Sunday shows - Infrastructure dominates MORE that an uptick of apprehensions and illegal border crossings last fall was evidence that Biden's inauguration had not triggered a surge of migration.

"This president inherited a mess from [President] Donald TrumpDonald TrumpEx-DOJ official Rosenstein says he was not aware of subpoena targeting Democrats: report Ex-Biden adviser says Birx told him she hoped election turned out 'a certain way' Cheney rips Arizona election audit: 'It is an effort to subvert democracy' MORE in terms of immigration, and he’s trying to fix it in a humane way," Murphy said.

"The surge at the border began last fall, in the last four months of Donald Trump’s presidency there was an 80 percent surge in apprehensions at the border," he added.

When Wallace pointed to numbers indicating a surge of migrants that was much higher over January and February, Murphy pointed out that the 11-year-high in border apprehensions occurred during the previous administration.

"This idea that it’s Joe Biden’s election that caused people to show up is belied by the actual facts," said the senator, adding: "It isn’t the policy of the U.S. that drives immigration, it’s the desperation [of migrants]."

Democrats have rallied to Biden's defense in response to growing calls from Republicans including House Minority Leader Kevin McCarthyKevin McCarthyPelosi, leaders seek to squelch Omar controversy with rare joint statement Omar: I wasn't equating terrorist organizations with democratic countries Schumer bemoans number of Republicans who believe Trump will be reinstated: 'A glaring warning' MORE (R-Calif.) for the administration to address surging numbers of border crossings, particularly by unaccompanied minors.

A CNN investigation last week found that thousands of children are being held in temporary shelters for longer than is legally permissible, with many sleeping on the floor and having little access to showers or other amenities.