High-level nuclear talks held Monday between the U.S. and Iran "made some progress" and managed to "sharpen up some of the tough issues," but there is still a "long way to go," according to one U.S. official, reported Reuters.

U.S. Secretary of State John Kerry met with Iranian Foreign Minister Mohammad Javad Zarif in Geneva for a second day of talks following a two-hour meeting on Sunday. U.S. Energy Secretary Ernest Moniz and Iran's atomic nuclear chief Ali Akbar Salehi also met for a second day.

Negotiators, which include the U.S. and five other major powers, will resume talks next Monday at an undecided venue and have set a deadline of March 31 to reach an initial deal.

"Both sides are determined to resolve the remaining issues," a senior Iranian official told Reuters. "Gaps still remain and the negotiators are trying hard to reach a common point."

The U.S. and five other world powers - Britain, France, Germany, Russia and China - are calling for Iran to reduce its ability to produce enriched uranium, and to get rid of some of the fuel it has already produced. World powers have long worried that Iran is on the verge of producing weapons-grade level fuel, but Tehran insists its nuclear program is for peaceful purposes only.

Iranian President Hassan Rouhani told the state-sponsored Islamic Republic News Agency on Monday that "no one now could claim that Iran is pursuing non-peaceful goals in its nuclear program."

Rouhani added that "those who are imposing sanctions against Iran as well as the ones who are running projects to make Iran's nuclear program a matter of security, are both well aware of the real objectives of Iranian nation and government."

Iranians have an inalienable right to gain access to nuclear technology for civilian purposes, Rouhani said, adding that Iranian citizens are suffering due to their determination to safeguard those rights.

Over the past few years, largely due to U.S.-led sanctions aimed at persuading Iran to stop its nuclear program, families living in poverty rose from 22 percent to more than 40 percent, the Rial has fallen at least 40 percent, and the price of foods such as milk, fruits and vegetables have skyrocketed, according to The New York Times. The shortage of western medical drugs and supplies has also jeopardized the health of millions.

As of late, many U.S. lawmakers have ramped up the call for increased sanctions, but President Barack Obama has held off, saying that additional sanctions at this point in the negotiation process would do more harm than good. Obama has vowed to veto any sanction bill that reaches his desk.