Republican Gov. Rick Perry of Texas said today he doesn't think President Obama "particularly cares" about the immigration problem he said is plaguing the United States' southern border, and charged that the administration has even sent "powerful messages" that people who cross the border illegally will be accepted.

During an exclusive interview this morning on "This Week," Perry said a key to solving the crisis is ensuring border security and he argued that is not something that the president is concerned about.

"I don't believe he particularly cares whether or not the border of the United States is secure," Perry said. "And that's the reason there's been this lack of effort, this lack of focus, this lack of resources," the Texas governor told ABC News' Martha Raddatz.

Perry, who has not ruled out a 2016 run for the White House, went further, saying the president has even encouraged the influx of immigration.

"The president has sent powerful messages time after time - by his policies, by nuances that it is OK to come to the United States and you can come across and you'll be accepted in open arms. That is the real issue," Perry said.

Raddatz asked Perry about comments he made on Fox News suggesting there was a conspiracy of sorts involving the Obama administration to get people into the United States. Perry did not seem to back off, and suggested the president may have an "ulterior motive."

"When I have written a letter that is dated May of 2012, and I have yet to have a response from this administration, I will tell you they either are inept or don't care, and that is my position," he said.

"We have been bringing to the attention of President Obama and his administration since 2010, he received a letter from me on the tarmac. He sends - I have to believe that when you do not respond in any way, that you are either inept, or you have some ulterior motive of which you are functioning from," he said

During an exclusive interview with George Stephanopoulos in late June, Obama, who called the situation at the border a " humanitarian crisis," encouraged parents to not send their children to the border.

"Do not send your children to the borders," he said. "If they do make it, they'll get sent back. More importantly, they may not make it."

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