Democrats and Republicans rallied against the US government's policy of separating parents and children at the Mexican border yesterday.

'This must not be who we are as a nation,' said Representative Jerrold Nadler, one of seven members of Congress from New York and New Jersey who met with five detainees inside a facility in Elizabeth, New Jersey, including three who said they had young relatives removed from their care after seeking asylum at the border.

The Fathers' Day events came as news stories highlighting the family separations intensified political pressure on the White House, even from some of President Donald Trump's fellow Republicans.

Opposition is being increasingly expressed by Christians, even evangelicals traditionally supportive of Republican administrations.

The president of the National Association of Evangelicals, Leith Anderson, the president of the Southern Baptist Convention's Ethics & Religious Liberty Commission, Russell Moore, and the president of the National Hispanic Christian Leadership Conference, Samuel Rodriguez, were among signatories to a highly critical letter to President Trump earlier this month from the Evangelical Immigration Table.

It said: 'The traumatic effects of this separation on these young children, which could be devastating and long-lasting, are of utmost concern.' It urges a reversal of the policy and calls for the US to 'resume a robust US refugee resettlement program'.

Opposition among Christians has increased since attorney-general Jeff Sessions quoted the letter to the Romans in support of the policy. Carl Lentz, the pastor of Hillsong Church in New York City known for his ministry to stars such as Justin Bieber, told MSNBC what was happening at the border was 'embarrassing' and that Sessions' interpretation of Romans was 'absolutely not' correct. 'We do have things that have to be followed with order,' he said. 'But if God's moral laws are violated, if the laws of compassion, if the laws of just what is right is violated, in this case, this thing with ripping apart families, it reminds me of our country when we had laws that said black people couldn't eat at certain restaurants.'

Lentz added, 'You can you prove a point of compassion throughout the entire Bible a lot easier than that man could do to approve a legislation that's literally ripping families apart today.'

Asked about a poll showing 72 per cent of white evangelicals backed Trump, he said he was hesitant to use the term 'evangelical' any more because it had been 'hijacked' by conservative evangelicals.

Writing for the Baptist Joint Committee on Religious Liberty, Don Byrd described Sessions' interpretation of Romans as 'theologically dubious and profoundly un-American'. 'We can and we should disagree about the meaning of Scripture, and debate which government policies are appropriate and just. But we do not worship the government or its laws. It is the government's job to protect our religious liberty, not to encourage religious fealty to its edicts,' he said.

Bishop Michael Curry, head of the Episcopal Church in the US, said on MSN.com that the policy of 'literally taking babies from their mothers' arms' was 'fundamentally, profoundly unChristian and it's un-American'. He said that 'St Paul is important, but for those of us who are Christians Jesus is Lord. And Jesus says love your neighbour, Jesus says love your enemy, Jesus says welcome the stranger.' He said Jesus, Mary and Joseph were refugees who fled persecution, adding 'Love of neighbour trumps everything.'

Rev Franklin Graham, a strong supporter of President Trump, said it was 'disgraceful, terrible to see families ripped apart and I don't support that one bit'.

The policy has even drawn criticism from Trump's wife Melania, who in a rare intervention said the US should 'govern with heart' and called on Republicans and Democrats to work together for 'successful immigration reform'.

Former First Lady Laura Bush said in a guest column for the Washington Post yesterday that the policy was 'cruel' and 'immoral' and 'breaks my heart'. She said the US government "should not be in the business of warehousing children in converted box stores or making plans to place them in tent cities in the desert outside of El Paso'.

The 'zero tolerance' policy has seen more than 2,000 children separated from their parents during the last six weeks.