The government is set to allow exports to third countries of a new type of ship-based missile interceptor being jointly developed by Tokyo and Washington, sources close to Japan-U.S. relations said Saturday.

Europe is considered a likely destination for the Standard Missile-3 Block 2A missile, an advanced version of the SM-3 series, if it is allowed to be shipped to third countries in a relaxation of Japan's decades-long ban on arms exports, the sources said.

U.S. Defense Secretary Robert Gates asked Tokyo to consider exporting SM-3 Block 2A missiles in a meeting with Defense Minister Toshimi Kitazawa last October. The move followed President Barack Obama's September announcement that Washington was abandoning plans for a missile defense shield in Eastern Europe.