TOKYO, March 23 -- Japanese Prime Minister Shinzo Abe eyes a U.S. visit from April 26 to May 3 for talks with U.S. President Barack Obama and the trip would make him the first Japanese leader to address a joint session of Congress.

Chief Cabinet Yoshihide Suga said Monday that the trip to the United States will bring Abe to Boston, Washington, San Francisco and Los Angeles, and the Abe-Obama talks is likely on April 28, a day after planned security talks between the two sides.

Suga said that the visit by Abe will "be significant in showing the robustness of the Japan-U.S. alliance to the world." Abe is expected to brief Japan move to deepen the alliance through crafting security-related bills, according to local reports.

However, the bilateral ties face a series of thorny challenges as governor of Japan's southernmost island prefecture of Okinawa on Monday order to suspend underwater work in the Henoko coastal area in Nago city in the prefecture for a relocation site for the U.S. Futenma airbase.

The governor, Takeshi Onaga, warned that if the Okinawa Defense Bureau does not follow the order, the Okinawa government would revoke in a week its permit granted to the bureau for rock drilling at the site.

The relocation plan of the U.S. airbase has for long troubled the Japan-U.S. alliance and relations between the prefecture and the Japanese central government. Anti-U.S. base sentiment is deep in Okinawa that holds a bulk of U.S. bases in Japan.

As to the U.S.-led Trans-Pacific Partnership free trade framework, Obama wants to reach a deal quickly so as to make it as his legacy to Democrats in presidential election, but lingering differences between Japan and the United States are regarded as a drag on the whole negotiations.

Meanwhile, the United States also urged Japan to improve its ties with neighboring countries. However, relations between Japan and its Asian neighbors, particularly South Korea and China, are still frayed due to Abe's administration's right-leaning and historical revisionism politics.