Image taken on April 21, 2011 shows wooden crosses on the border wall between Mexico and the United States in Tijuana city, Mexico. On Jan. 25, 2017, U.S.President Donald Trump signed an executive order for a border wall to be built, but Center for Latin American Monetary Studies (CEMLA) estimated that migration from Mexico has been slowing down since 2008 after growing from 1990 to its peak in 2007. (Xinhua/Guillermo Arias)

WASHINGTON, Feb. 21 (Xinhua) -- The U.S. Department of Homeland Security (DHS) on Tuesday released detailed policies on crack downs of illegal immigrants, which included bolstering border protection agencies and closing policy loopholes.

The new policies were designed "to stem illegal immigration and facilitate the detection, apprehension, detention and removal of aliens who have no lawful basis to enter or remain in the United States," said a document titled "Implementing the President's Border Security and Immigration Enforcement Improvements Policies."

The paper, along with the Memorandum for the Enforcement of the Immigration Laws to Serve the National Interest, were signed Monday by John Kelly, the secretary of the DHS.

Major steps outlined in the papers include hiring more Customs and Border Protection agents, expanding a program that gives Kelly more power in directing field operations, initiating a wall along the U.S.-Mexican border, and stepping up the effort to "return aliens to contiguous countries."

The border security memo stated that it "constitutes guidance to all department personnel, and supercedes all existing conflicting policy, directives, memoranda, and other guidance regarding this subject matter."

The memos came in the wake of two executive orders signed by U.S. President Donald Trump in late January aimed at enhancing border security and restricting illegal immigrants across the country.

Another related executive order from Trump, which imposed a temporary ban on immigrants and citizens of seven Middle Eastern countries, was scrapped after federal judges ruled against it.

The status of illegal immigrants in the United States have become a contested subject especially among many of the liberal-leaning coastal states, in which many cities and counties have declared to be sanctuaries for illegal immigrants.

Federal agents have conducted raids across the country and arrests hundreds of illegal immigrants in recent weeks, according to media reports.