Will evaluate US troop presence in Afghanistan if elected: Hillary Clinton

Democratic presidential frontrunner Hillary Clinton has said she would "make an evaluation" of US troop presence in Afghanistan if elected, citing an "arc of instability" after the Islamic State created its outposts in the war-torn country.

"I would have to make an evaluation based on the circumstances at the time I took office as to how much help they continue to need. Because it's not just the Taliban. We now are seeing outposts of fighters claiming to be affiliated with ISIS," Clinton said.

"We've got this arc of instability from North Africa to South Asia, and we have to pay close attention to it. We have to build coalitions...And what I will do as president to make sure that we defeat these terrorist networks," Clinton said during a Democratic debate ahead of the New Hampshire primary.

President Barack Obama had said he would trim the US force in Afghanistan to 5,500 troops by the end of last year, and then further cut the presence to 1,000 by the end of 2016. But he backtracked, saying the situation remained too fragile for such a rapid withdrawal.

Of late, the Afghan security forces have suffered major setbacks, including a brief Taliban capture of Kunduz city.

"We have a very cooperative government there with President Ashraf Ghani and his top partner, Abdullah Abdullah. They are doing their very best. The Afghan army is actually fighting, taking heavy losses defending Afghan territory," she said in response to a question.

On the US involvement in Syria and Libya, Clinton endorsed Obama's administration's policy of supporting the Arab and the Kurdish fighters, "who are actually doing the fighting."

Clinton ruled out sending US troops to the two countries, noting that she supports special forces and air campaigns.

"We're doing the support and enabling. I also think we've got to do more to stop foreign fighters, foreign funding and take ISIS online, as well as doing everything necessary to keep us safe at home. So as I look at what the president it doing, it adds up to me," Clinton said.

Heading into the debate, her rival Bernie Sanders said troops from Afghanistan can't be withdrawn overnight. "You can't simply withdraw tomorrow. Wish we could, and allow the Taliban or anybody else to reclaim that country," he said.

Clinton is trailing behind Sanders by a huge margin in New Hampshire, but is leading nationally. She has won the Iowa caucuses earlier this week by a razor-thin margin. The race for the Democratic nomination, once seen as a sure thing for Clinton, has intensified since then.

The debate is the last before Tuesday's first-in-the- nation New Hampshire primary.

On the US involvement in Iraq and Syria, Sanders said some progress has been made with the Iraqi army finally taking control of the crucial city of Ramadi from the Islamic State.

"ISIS has lost I think 40% of the territory that it held in the last year," he said, using an acronym for the militant group.

Sanders said the great task is to make sure that young men and women in the military do not get sucked into never-ending, perpetual warfare within the quagmire of Syria and Iraq.

"I will do my very best to make sure that that doesn't happen. I agree with Secretary (Clinton)," he said.

He also said that Jordan's King Abdullah "hit the nail on the head."

"What he said is essentially the war against ISIS is a war for the soul of Islam. It must be Muslim troops on the ground that will destroy ISIS, with the support of a coalition of major powers - US, UK, France, Germany and Russia," he said.

"So our job is to provide them the military equipment that they need, the air support they need, special forces when appropriate," Sanders said.

He said that the combat on the ground "must be done by Muslim troops with our support."

"We must not get involved in perpetual warfare in the Middle East," Sanders said.