GENEVA, Dec. 16-- Delegations from U.S. and Iran continued bilateral meetings here on Tuesday over Tehran's disputed nuclear program after Monday's engagements between the two sides.

A diplomatic source with the U.S. Mission in Geneva confirmed to Xinhua that Tuesday's talks has begun, and were expected to last all day long.

Iranian official media Tasnim news agency reported that Monday's talks lasted about 6 hours and the time length was also confirmed by the U.S. diplomatic source to Xinhua.

According to Tasnim, Iran's deputy foreign minister Abbas Araqchi, who heads the Iran's delegation, said that Monday's meeting covered "extensive discussions on the entire subjects, particularly on the issue of sanctions".

Araqchi's announcement was believed to be true by the U.S. source who added that all issues related to Iran nuclear program would be on the table at Tuesday's meetings.

Araqchi reportedly said that the discussions have now become "very detailed", and there are solutions to some differences, while some others would require more efforts and discussions.

Moreover, Tasnim reported that Araqchi said the Iranian team will hold separate bilateral meetings this evening with other members of the P5+1 group, namely China, France, Russia, U.K., U.S., plus Germany.

These bilateral consultations were held ahead of the new round of meetings between the P5+1 group and Iran scheduled on Wednesday, weeks after the failure to meet a Nov. 24 deadline for a comprehensive nuclear deal.