U.N. Secretary-General Ban Ki-moon on Sunday promised to lend his personal support to rival Cypriot leaders who are locked in complex talks aimed at reunifying the ethnically divided island nation.

Ban Ki-moon said he and the U.N. will personally do "their utmost" to assist Greek Cypriot leader Nicos Anastasiades and Turkish Cypriot leader Mustafa Akıncı resolve the decades-old problem.

Following the one-and-a-half hour meeting with the leaders, Ban praised the two men for their decision to intensify negotiation efforts with aims to reach a reunification deal in 2016.

Ban, who met with both leaders Sunday, called on them to "make the most" of the time ahead to overcome hurdles still impeding an accord.

Ban said he stands ready to help both sides in whatever capacity they require, including "international dimensions" of the issue — an indirect reference to intervention rights that were ceded to Greece, Turkey and the U.K. under the Constitution of Cyprus since it gained independence from British rule in 1960.

He added that he would like to see a final settlement of the Cyprus conflict before he steps down from his position as U.N. chief on Dec. 31.

"The period ahead [of us] will be crucial for Cyprus," Ki-moon said after the meeting. "Time is of the essence."

Both leaders Anastasiades and Akıncı have said they aim to reach a deal by year's end. Anastasiades said Sunday the target for a 2016 deal still stands, although he called it "ambitious."

After meeting with Ban on Saturday, Akıncı said he expected a "road map" to be agreed upon during the trilateral meeting to turn recent progress in the talks into a "real success story."

Akıncı also said he told the U.N. secretary-general that talks should take on a new "format" where key aspects of a deal — including how much territory would be ruled by each side - would be hammered out.

He also pointed to what he called risks of allowing talks to drag on beyond the end of the year. Elections in the south are slated for February of 2018.

Anastasiades said no deadlines, time frames or third-party arbitration were imposed on negotiations during the meeting with Ki-moon.

He also said negotiations would be stepped up when he and Akıncı return to the island.

Negotiations are centered on the creation of a new bi-communal Cyprus Federation, but there have been differences over divisive issues of property and territorial adjustments that could see a number of Turkish Cypriots displaced from their homes.

Any agreement the two leaders reach will have to be put to simultaneous referendums on either side of the island.

Reunification talks between the Greek Cypriot and Turkish Cypriot communities on the island resumed in May 2015 when newly elected Akıncı met with Greek Cypriot leader Nicos Anastasiades. Previous negotiations were stalled in October 2014 in a row over gas exploration.

A previous peace deal brokered by then-U.N. Chief Kofi Annan in 2004 was backed by a significant majority of Turkish Cypriot voters but overwhelmingly rejected by their Greek Cypriot counterparts.

The island has been divided with a Turkish Cypriot government in the northern third of Cyprus and a Greek Cypriot administration in the south since the 1974 Greece-backed military coup on the island which was followed by Turkey's military intervention as a guarantor power.