Iran’s Mohammad Javad Zarif and his US counterpart held three rounds of talks in short intervals on Wednesday.

The bilateral meeting was part of efforts to narrow down the differences in the course of nuclear talks between Iran and the Group 5+1 (Russia, China, the US, Britain, France and Germany).

"On Wednesday, I will discuss with Kerry only the nuclear negotiations to see whether it is possible to accelerate and advance the talks," Zarif said on Sunday.

"We believe that sanctities need to be respected," Zarif told reporters minutes before a meeting with his US counterpart in the Swiss city of Geneva on Wednesday.

"Unless we learn to respect one another, it will be very difficult in a world of different views and different cultures and civilizations, we won't be able to engage in a serious dialogue if we start disrespecting each other's values and sanctities," Zarif added.

Their meeting in Geneva aimed at accelerating pace of negotiations between Iran and the 5+1.

Zarif said on January 14 that his meeting with his US counterpart was vital for progress on talks on Tehran's contested nuclear drive. Under an interim deal agreed in November 2013, Iran's stock of fissile material has been diluted from 20 percent enriched uranium to five percent, in exchange for limited sanctions relief.

Done with his talks with Kerry, Zarif is to leave Geneva for Berlin to meet his German counterpart Frank-Walter Steinmeier on Thursday while his deputies are to resume talks with their American counterparts in Geneva.

On January 18, Iran and the group of six world powers (alternatively known as the P5+1 or E3+3) will resume talks at the deputy ministerial level.

Negotiations between Iran and the sextet aim to hammer out a final agreement to end more than a decade of impasse over Tehran’s peaceful nuclear program.