The United States is considering deploying more regional missile-defense systems in the Pacific to counter North Korea, the Pentagon’s second-ranking officer said Tuesday.

Adm. James A. Winnefeld Jr. said that as the United States faces an era of declining budgets, it is likely that Washington will increasingly rely on its allies to protect themselves from the threat of ballistic missiles. But he highlighted the deployment last year of a U.S. Army battery manning an advanced missile-defense system in Guam and left open the possibility that the United States may make similar moves in the future.

“There it remains, readily deployable if necessary to somewhere else in the world if needed, but in the meantime defending U.S. soil from potential threats,” Winnefeld said of the system in Guam. “And with the unpredictability of the North Korean regime, we may find ourselves doing more of this sort of thing in the future elsewhere in the region.”

The comments came as the Pentagon is reportedly exploring the idea of placing a similar system in South Korea. He did not mention that during his remarks Tuesday but said the United States continues to rely on “strong bilateral alliances in the Pacific with South Korea, Japan and Australia.” South Korea is thought to be hesitant to participate in a regional missile shield with the United States and Japan, preferring to develop its own instead.

Winnefeld’s remarks, delivered at the Atlantic Council’s global missile-defense conference in Washington, came a little more than one year after the Obama administration announced a $1 billion expansion to its missile-defense program to counter the possibility of a nuclear attack by North Korea using intercontinental ballistic missiles.

Vice Chairman of the Joint Chiefs of Staff James Winnefeld defended the development of the next generation of interceptor missiles. (Chip Somodevilla/Getty Images)

The plan calls for the installation of 14 new ground-based interceptor missiles at Fort Greely in Alaska, approximately a 50 percent increase over the number of missiles the Pentagon has on the West Coast.

The admiral, who is vice chairman of the Joint Chiefs of Staff, defended the development of the next generation of interceptor missiles, following the failure of a missile that missed its target over the Pacific last summer. Winnefeld said that the test missile “flew perfectly until I watched it fail in the last couple seconds” and that the military is preparing to launch another test run against a moving target.

“If it is a success, candidly, it will be a very good shot in the arm for the program, and we will resume production on 14 more ‘in progress’ missiles,” he said.

Winnefeld’s address also included strong words about Russia, whose relationship with the United States has deteriorated to levels not seen since the Cold War after the annexation of Crimea and unrest in eastern and southern Ukraine.

The admiral did not mention the crisis in Ukraine but stressed that the powerful Aegis missile shield that the Pentagon is erecting in Eastern Europe is not meant to counter Russia’s nuclear arsenal but to handle threats from the Middle East. Russia has protested aspects of U.S. missile defense in Europe for years, saying that Washington is covertly trying to counter the Kremlin’s intercontinental ballistic missiles.

“Let me be clear once again: It is not the policy of the United States to build a ballistic missile defense system to counter Russian ballistic missiles,” Winnefeld said. “The Aegis Ashore sites in Poland and Romania are designed to counter long-range ballistic missiles that may be launched from other nations, outside of the Euro-Atlantic area, against our European NATO partners.”

On South Korea, the admiral included one quip, saying that the United States is “not betting on Dennis Rodman as our deterrent against a future North Korean ICBM attack.”

The retired NBA basketball star has struck up an unusual friendship with North Korean dictator Kim Jong Un, traveling to North Korea twice in the last year, against State Department wishes, to meet with him. Rodman said at one point that he wanted to bridge the gap between Americans and North Koreans.