Iran's Rouhani calls on Japan to rescue nuclear deal
In the tenth meeting of the two leaders, Rouhani expressed his hopes that Japan and "other countries in the world" would strengthen their efforts toward maintaining the nuclear agreement.
Japan, a historic US ally, enjoys close relations with Iran.
In the meeting's opening remarks, the Japanese prime minister urged his counterpart's nation to "fully comply" with the agreement, as well as playing a positive role for "peace and stability in the region".
Following re-imposition of US sanctions on Iran, Japan, which had been one of the largest purchasers of Iranian oil, stopped all imports in May.
The Middle East supplies more than 80 percent of Japan's oil.
Despite widespread speculation on Japan's role as a mediator, Iranian state media have reported that Rouhani's visit has little to do with "restarting negotiations with America".
In June, Prime Minister Shinzo Abe visited Tehran, with the aim of presenting himself as mediator between the US and Iran.
The first Japanese premier to visit the Islamic Republic since its inception, his efforts to bring the two sides to the negotiating table proved fruitless.
Abbas Mousawi, spokesman for the Iranian Foreign Ministry, remarked that Friday's discussions would instead revolve around the fate of "the nuclear deal" and "developments in the region".
Rouhani, for his part, has maintained that direct talks with the US can only resume on the condition that Washington lift its "unlawful" sanctions.
Abe is also expected to propose a contentious plan to deploy military resources to the Middle East in his encounter with Rouhani, to ensure the safety of Japanese oil tankers.
Prior to leaving Malaysia, Rouhani announced that the security of ships in the region would be on the agenda in his meeting, according to BBC Persian.
A tanker bearing a Japanese flag was attacked on approach to the Gulf of Oman at the time of Abe's visit to Tehran in June.
The US held Iran responsible and called on Japan to join a US-led naval defence coalition operating in the region, which Japan declined.