WASHINGTON — President Barack Obama and Japanese Prime Minister Yoshihiko Noda on Monday decried aggressive acts from North Korea, including its recent failed rocket launch, and vowed to maintain a unified front against such provocations.

Obama said Pyongyang is operating from a position of weakness, not strength, and Noda said the launch undermined diplomacy to contain North Korea’s nuclear ambitions.

Obama said the U.S. and Japan, along with other countries in the region are unified in insisting that North Korea abide by its international responsibilities.

“The old pattern of provocation that then gets attention and somehow insists on the world purchasing good behavior from them, that pattern is broken,” Obama said in a joint news conference with Noda at the White House.

Such actions, Obama said, “only serve to deepen Pyongyang’s isolation.”

North Korea fired a three-stage rocket earlier this month over the Yellow Sea, defying international warnings against what the U.S. and other nations said would violate bans against nuclear and missile activity. In response to the launch, the U.S. suspended an agreement to provide food aid to North Korea.

Noda, standing next to Obama in the White House East Room, said that given North Korea’s past practice, there appeared to be a good chance that it would undertake yet another nuclear test. The Japanese prime minister said China remains an important player in trying to restrain North Korea’s nuclear program.

Noda was in Washington looking to reaffirm Japan’s strong alliance with the U.S. and to boost his leadership credentials as his popularity flags at home.

Noda, who came to power in September and is Japan’s sixth prime minister in six years, faces huge challenges in reviving a long-slumbering economy and helping his nation recover from the worst nuclear crisis since Chernobyl.

His Oval Office meeting and working lunch with Obama, as well as the news conference followed by a gala dinner hosted by Secretary of State Hillary Rodham Clinton, could offer Noda some brief relief from domestic woes. The two sides are determined to show that U.S.-Japan ties are as close as ever, particularly after the assistance from the U.S. lent following the massive March 2011 earthquake and tsunami that triggered a meltdown at a nuclear plant.

Obama praised Noda and the Japanese people for their recovery after the disasters.

The U.S. alliance with Japan, the world’s third-largest economy, is at the core of Obama’s expanded engagement in Asia — a diplomatic thrust motivated in part by a desire to counter the growing economic and military clout of strategic rival China.

Their meeting takes place during a delicate time in U.S.-China relations, as the two world powers reportedly negotiate an asylum deal for a blind Chinese legal activist who escaped from house arrest. Activists say he is under the protection of U.S. diplomats in Beijing, but Obama would not comment on the diplomatically sensitive case during the news conference.

He did add, however, that the issue of human rights is a recurrent one in U.S. meetings with China.

“It is our belief that not only is that the right thing to do because it comports with our principles and our belief in freedom and human rights, but also because we actually think China will be stronger as it opens up and liberalizes its own system,” he said.

Obama and Noda said they want to strengthen the U.S.-Japan security alliance. The U.S. has about 50,000 troops in Japan, and both sides never tire of saying that their defense cooperation underpins regional peace and security.

Days before Noda’s visit, the U.S. and Japan announced an agreement to shift about 9,000 Marines stationed on the Japanese island of Okinawa — an announcement Obama reiterated Monday. The plan would spread U.S. forces more widely in the Asia-Pacific as part of a rebalancing of U.S. defense priorities after a decade of war in Iraq and Afghanistan.

It is a move also aimed at easing what Okinawans view as a burdensome U.S. military presence and goes some way to ameliorate a long-term irritant in bilateral relations. But there’s still no timetable and the plan faces opposition in Okinawa and in the Congress.

Noda is the first Japanese leader to be hosted at the White House since his Democratic Party of Japan, which had an initially awkward relationship with Washington, came to power in the fall of 2009. The party had at first favored a foreign policy more independent of the United States.

Noda is seen in Washington as capable and practical. The Obama administration hopes he can weather his political problems and stick around longer than his immediate predecessors. His support in polls has dwindled to below 30 percent as he pushes an unpopular rise in a consumption tax to tackle Japan’s vast national debt and looming social security crisis to cope with the nation’s aging population.

No breakthroughs on trade were anticipated at Monday’s summit. Obama said both sides would continue discussions about Japan’s interest in the Trans-Pacific Partnership, a pact under negotiation by nine nations and a key plank in U.S. trade strategy to crank up its exports to support America’s fragile recovery after the global slowdown.

While Noda is believed to be personally supportive of declaring Japan’s intent to join the talks, he faces opposition at home, even within his own party. The pact could demand an assault on the heavy subsidies enjoyed by Japan’s farmers.