No problem with supplies after tanker attacks: Japan
However, Tokyo maintained that it is communicating with the United States over the issue, Japanese Kyodo news reported.
Addressing a news conference, Japan's Economy, Trade and Industry Minister Hiroshige Seko said: "Although there will be no problem with stable supply of energy, we will continue to monitor the relevant information."
Two oil tankers, one of them was operated by a Japanese company, were attacked on Thursday in the Gulf of Oman while on their way to Asia from Qatar and Saudi Arabia.
After the explosion, the two tankers called for emergency assistance of the countries around the Gulf.
At least 44 people in the tankers were evacuated and transferred to Bandar-e-Jask port in southern Hormozgan province of Iran, according to IRNA, the official news agency of Iran.
The attacks took place when Japanese Prime Minister Abe Shinzo was on a landmark trip to Iran for talks with the Middle East country's leaders aimed at easing tensions between Tehran and Washington.
Speaking about the incident, Japan's Transport Minister Keiichi Ishii on Friday said: "We have not learned who carried out the attacks and how."
U.S. has squarely blamed Iran for the attacks near the strategically important sea lane.
However, Iran's Foreign Minister Javad Zarif said the attacks were "suspicious" for having been perpetrated during talks between the Japanese premier and the country's Supreme Leader Ali Khamenei.
"Suspicious doesn't begin to describe what likely transpired this morning," Zarif said on Twitter, adding that "Iran's proposed Regional Dialogue Forum is imperative."
Abe's Chief Cabinet Secretary Yoshihide Suga said in Tokyo that the Japanese government is "closely collaborating and exchanging information with the United States".