As a caravan of thousands of migrants from Central America continues its trek north to the United States, the U.S. bishops' conference and leaders of Catholic aid agencies have urged government officials to treat migrants compassionately.

Signers of the joint statement, released on Monday, included Bishop Joe Vásquez of Austin, chairman of the U.S. Bishop's committee on migration, Sean Callahan, President and CEO of Catholic Relief Services, and Sr. Donna Markham OP, President and CEO of Catholic Charities USA.

"We affirm that seeking asylum is not a crime," they said in their statement.

"We urge all governments to abide by international law and existing domestic laws that protect those seeking safe haven and ensure that all those who are returned to their home country are protected and repatriated safely," they said.

Earlier this month, a group of about 160 migrants in Honduras started a migrant caravan, trekking northward to seek asylum as refugees in the United States. That caravan, which is now in Mexico, is believed to have peaked at 7,000 people, although several hundred have reportedly dropped off or fallen behind at various points.

Other smaller caravans have also started making their way north to the U.S., including a caravan of about 200 people from El Salvador.

The President of Mexico, Enrique Peña Nieto, has offered benefits such as temporary work permits and medical care to migrants who want to stay in the country, but at least 4,000 people are continuing the journey to the United States.

Catholic Churches along the route in Mexico have provided places of brief rest and refreshment, the Washington Post reported.

On Monday, U.S. President Donald Trump called the caravan "an invasion" and announced that 5,200 troops will be deployed to the U.S.-Mexico border by the end of the week to work with U.S. Customs and Border Protection to ensure enforcement of immigration laws.

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"Many Gang Members and some very bad people are mixed into the Caravan heading to our Southern Border," Trump tweeted on Monday. "Please go back, you will not be admitted into the United States unless you go through the legal process. This is an invasion of our Country and our Military is waiting for you!"

In their statement, Vásquez, Callahan and Markham said they have helped assist the poor and vulnerable in the U.S. and throughout the world, and they "deeply saddened by the violence, injustice, and deteriorating economic conditions forcing many people to flee their homes in Central America. While nations have the right to protect their borders, this right comes with responsibilities: governments must enforce laws proportionately, treat all people humanely, and provide due process," they said.

They also urged the government to address not only the migrants that come to the U.S., but to work to address the regional issues that force migrants to leave their homes, such as violence and lack of economic opportunity in their countries.

"An enforcement-only approach does not address nor solve the larger root causes that cause people to flee their countries in search of protection," they said.

"As Christians, we must answer the call to act with compassion towards those in need and to work together to find humane solutions that honor the rule of law and respect the dignity of human life."

The migrant caravan is still 900 miles from the United States, but is expected to reach the border in the next few weeks.