On Sunday, Hillary Clinton expressed concern over the foreign policy view of Donald Trump. (File Photo)

Democratic White House aspirant Hillary Clinton on Sunday expressed concern over the foreign policy view of Republican presidential front runner Donald Trump."I think it's quite concerning," Ms Clinton told CNN in an interview when asked about the recent foreign policy speech of Trump early this week."His (Trump) talk about pulling out of NATO, his talk about letting other countries have nuclear weapons, which runs counter to 70 years of bipartisan national security policy, his idea that he -- quote -- "has a secret plan" to get rid of ISIS and he's not going to tell anybody, I find it disturbing because I know that the stakes are high, that we face some real challenges and dangers in the world," she said. Ms Clinton was the Secretary of State in the first term of the Obama Administration.President Barack Obama has described her as one of the most successful US Secretaries of State."I don't think loose talks about loose nukes, I don't think turning our back on our strongest allies, I don't think pretending you have some sort of secret plan is a very smart way to go forward in leading the world, which is what we must do," the former top American diplomat said.Responding to a question on use of military force, she said she supports using this only as a last resort."It's not a first choice. As Secretary of State, I talked about smart power, about diplomacy and development. So when you have somebody who says he's going to be tough and he's going to get results, but he doesn't tell you how he's going to do it, I think we will have a lot to contrast with," she said. Ms Clinton refused to the Trump's attack on her as a "crooked" Hillary."He can say whatever he wants to say about me. I could really care less. I'm going to stand up for what I think the American people need and want in the next president,"she said."That's why I have laid out very specific plans. There's nothing secret about what I want to do with the economy, with education, with health care, with foreign policy. I have laid it all out there. And he can't or he won't. I can't tell which. So we're going to talk about what we want to do for the country, and he can continue on his insult fest, but that's the choice he's making," Ms Clinton said.Mr Trump meanwhile continued with his attack on Ms Clinton."The fact is, the only card she has is the woman's card."She's done a lousy job in so many ways and even women don't like her. They don't like her," he said."But it is the woman's card and she plays it, and I'll let you know in about six months whether or not she plays it well. But I don't think she'll play it well. And it's true, if she were not a woman, she wouldn't even be in this race," he said."I'll be much tougher than her, I will have much more respect than her from foreign countries. In fact, I read today where they're very concerned with me, they feel I'm very strong, very tough and they're very concerned. So, that's a little opposite of what you're telling me. That's a psychological thing which frankly is good. Let them be a little concerned," he said.