In an exchange with reporters in Texas Wednesday, Obama said it would be premature to discuss the possibility of asking rival Sen. Hillary Clinton to be on the ticket, The Politico reports.

"We are just focused on winning the nomination. That is my focus." Obama said before leaving Texas. "I respect Sen. Clinton. She has been a tenacious opponent. It is premature to talk about a joint ticket."

Obama hinted to reporters that he would be taking a tougher line against Clinton in the coming weeks.

"I hope people start asking is what exactly is this foreign experience she is claiming," he said. "I haven't seen any evidence that she is more equipped to handle a crisis."

Obama said he believes he is in a much stronger position to run against the Republicans.