Donald Trump Wednesday said he will deliver a "major" speech Wednesday in Arizona on illegal immigration, apparently setting a deadline for a much-anticipated clarification of his views on the topic.

"I will be making a major speech on ILLEGAL IMMIGRATION on Wednesday in the GREAT State of Arizona. Big crowds, looking for a larger venue," Trump tweeted.

Trump has acknowledged he is "softening" his position, drawing fire from some conservatives who had backed his original plan to deport all illegal immigrants. Comments by Trump aides in recent days suggest he will focus his deportation effort on criminal illegal aliens.

The Arizona speech had originally been billed as an immigration speech, but then Trump aides suggested it would be about something else. Now, amid pressure for him to outline his views, the immigration speech is back on.