Washington, Jun 18 (IANS): US Democrat lawmakers have expanded their campaign highlighting President Donald Trump's administrations forced separation of migrant children from their families at the Mexico border, a media report said.

Against a notable silence on the part of many Republicans, the Democratic lawmakers on Sunday visited a detention centre outside New York City and headed to Texas to inspect facilities where children have been detained, reports The Washington Post.

In McAllen, Texas, where several Democratic lawmakers toured a facility, state Representative Vicente Gonzalez estimated that he saw about 100 children younger than six.

"It was orderly, but it was far from what I would call humane," he said.

Seven Democratic members of Congress spentSunday morning at the Elizabeth Contract Detention Facility in New Jersey, waiting nearly 90 minutes to view the facilities and visit five detained immigrants.

"This is unfair and unconstitutional," said New York Representative Adriano Espaillat.

Trump has falsely blamed the separations on a law he said was written by Democrats, The Washington Post reported.

But the separations instead largely stem from a "zero-tolerance" policy announced last month by Attorney General Jeff Sessions.

The White House also has interpreted a 1997 legal agreement and a 2008 bipartisan human trafficking bill as requiring the separation of families, a posture not taken by the previous two administrations.

Trump remained silent on the issue before tweeting on Sunday evening that Democrats should work with Republicans on an immigration solution before the midterm elections "because you are going to lose!"

US officials have said that the number of families who could be broken up might double and that the number of children who have already been taken from their parents -- 2,000 over a six-week period from April to May -- may be higher than what the administration has reported.