WASHINGTON

Secretary of State John Kerry urged his Russian counterpart Wednesday to use Moscow’s influence with the Syrian government to ensure greater humanitarian access in the war torn country.

During a meeting with Sergey Lavrov in the Swiss city of Zurich, Kerry “pressed for Russia to use its influence with the Asad regime to ensure immediate, unimpeded and sustained humanitarian access to all Syrians in need, especially those in besieged areas such as Madaya,” State Department spokesman John Kirby said in a statement, using the U.S. government’s preferred spelling of the Syrian president’s last name.

The two leaders also discussed preparations for negotiations between the country’s warring parties scheduled for Jan. 25 as well as “the importance of maintaining progress toward a diplomatic solution to the crisis in Syria”.

The talks are the first step in what is to be an 18-month political process aimed at ending Syria’s nearly six-year civil war.

A continued sticking point between Assad’s allies, Iran and Russia, and the U.S. and its Arab and Turkish allies is the decision on which opposition groups should be excluded from talks and considered terrorists.

There is particular disagreement about the Islamist groups Ahrar as-Sham and Jaish al-Islam.

Kerry will visit Saudi Arabia over the weekend in part to discuss Syria’s beleaguered political transition. While meeting with Lavrov, the leaders also discussed the situation in Ukraine where violence has persisted in the east of the country.

A response to North Korea’s recent nuclear test was also discussed.