U.S. President Donald Trump is planning to sign more executive orders on Wednesday that will enable the construction of his wall along the border between the U.S. and Mexico and target sanctuary cities where leaders will not hand over undocumented immigrants to be deported, said officials at the White House.

The actions are part of a number of days focused on immigration and amongst a myriad of immediate and sweeping changes to the immigration system in the U.S. under consideration by Trump.

These moves represent the first effort by Trump to deliver on what is considered by many as his signature issue that helped drive his campaign to the White House, which is the belief he has that illegal immigration remains out of control and threatens the security and safety of the country.

The blitz by Trump on immigration this week has been seen inside his administration as a victory for the populist wing within his inner circle that includes Stephen Bannon his chief strategist, Jeff Sessions his nominee for attorney general and Stephen Miller his policy advisor.

However, on Tuesday discussion continued about how far to move forward with some policies. In particular the program of Deferred Action for Childhood Arrivals, which is DACA, an initiative from 2012 that gave temporary protection from being deported to hundreds of thousands, who arrived in the U.S. as children.

During his presidential campaign, Trump promised to reverse DACA.

However, late Tuesday it was still not clear whether DACA was to be part of the immigration issues addressed by Trump, said one official in the White House.

This is due to differing views amongst advisers to Trump and associates over the scope, timing and benefits politically of bringing the program to an end or suspending it for newer entries.

Officials are also considering, without a final decision as of yet, whether to shut down indefinitely the program that allows refugees from Syria into the U.S.

The White House crackdown on sanctuary cities will resonate with the entire Republican base, which has criticized for a long time local officials who will not cooperate with immigration authorities at the federal level.

Any measures announced on immigration by Trump will create a fierce battle in the first week of his presidency between his administration and immigrant advocates, who reacted with alarm on Tuesday as immigration was coming to the table to be discussed by his administration.

Next week, Mexican President Enrique Pena Nieto is scheduled to meet with Trump in Washington.