Reuters - Iran has proposed President Hassan Rouhani visit Japan, a U.S. ally which also has close relations with Tehran, to try to resolve Iran�s nuclear impasse with Washington, Kyodo news agency reported on Tuesday.

Citing a senior diplomatic source, Kyodo said Iran�s deputy foreign minister for political affairs Abbas Araqchi had relayed the proposal to Japan during a two-day visit to Tokyo as a special envoy of Rouhani.

�Iran is seen as hoping to realize such a visit at an early date while Japan is expected to examine it carefully,� it said.

Japan maintains friendly ties with both the United States and Iran and has previously tried to ease tension between the two countries, which severed diplomatic relations shortly after Iran�s 1979 Islamic revolution that toppled the U.S.-backed Shah.

In Tokyo, a Japanese Foreign Ministry spokesman said he had no information regarding any possible trip to Japan by the Iranian president.

Tensions have heightened between Tehran and Washington since last year when President Donald Trump pulled out the U.S. from Tehran�s 2015 nuclear deal with six powers and reimposed sanctions on the country that have crippled its economy.

Japanese Prime Minister Shinzo Abe, who has forged warm relations with Trump, traveled to Iran in June to persuade Iran and the United States to resume direct talks and dial down tension. Iran has ruled out talks with Washington unless it returns to the nuclear deal and lifts all sanctions on Iran.

In response to Washington�s �maximum pressure�, Iran has gradually scaled back its commitments under the deal, which curbed Tehran�s nuclear program in exchange for lifting most international sanctions.

Japan, which has stopped buying oil from Iran because of U.S. sanctions, is keen to see stability in the Middle East, where the bulk of its oil imports come from.

In October Japan said it planned to send a naval force to Middle East waters to guard ships supplying Japan, but declined to join any U.S. coalition to protect merchant vessels.

Iran has criticized the U.S. efforts to build an alliance to protect shipping in the Gulf, saying countries in the region can protect waterways used by oil tankers.

Writing by Parisa Hafezi, Additional reporting by Timothy Kelly in Tokyo, Editing by William Maclean