President Barack Obama and Japanese Prime Minister Shinzo Abe spoke by phone Wednesday, days after the US leader met over the weekend with the president of China, the White House said in a statement.
The two leaders "discussed the president's recent meetings with President Xi Jinping of China, and agreed on the importance of ensuring stability and pursuing dialogue as it relates to the East China Sea," the statement read.
The reference to the East China Sea relates to Japan's dispute with China over the Senkaku Islands, which China calls the Diaoyus.
On Tuesday Japan and the United States started a joint drill to practice retaking remote islands, the Japanese government said, as Tokyo and Beijing continue to face off over ownership of the Tokyo-administered archipelago.
The United States has studiously avoided taking a position on the sovereignty of the islands, but has said they are covered by a mutual defense treaty.
Abe, seen as a hardliner against China, has stepped up defense spending by the world's third largest economy and taken an uncompromising stance on the islands.
During the phone call, Obama also "stressed" that Washington "looks forward to being able to welcome Japan to the Trans-Pacific Partnership (TPP) negotiations as early as possible once current TPP members complete their domestic requirements."
With the entry of Japan into the free-trade talks the pact would cover nearly 40 percent of the global economy, making it the biggest free-trade agreement in the world.
The bloc is aimed creating a tariff-free zone with a market of around $25 trillion covering some 800 million people.
Obama and Abe also "pledged to continue to work together closely toward the elimination of North Korea's nuclear and ballistic missile programs," and the two leaders "expressed the shared desire to work together closely at the up-coming G8 Summit in Northern Ireland," the brief statement read.