U.S. Defense Chief Warns of Al Qaeda’s Gains in Yemen

TOKYO — Al Qaeda’s affiliate in Yemen is seizing territory, exploiting the recent turmoil in the country to capture areas in what has become a broad expansion by the Sunni extremist group, Defense Secretary Ashton B. Carter of the United States said on Wednesday.

Calling the situation “obviously very unsettled,” Mr. Carter said that the war in Yemen had left a number of groups vying for power, including Al Qaeda in the Arabian Peninsula, also known as A.Q.A.P., an enemy of the United States.

“A.Q.A.P.,” Mr. Carter said, “has seized the opportunity of the disorder there and the collapse of the central government.”

He warned that the group had “ambition to strike Western targets including the United States” and said that American counterterrorism efforts had been stymied by the fall of the Yemeni government.

“Obviously it’s always easier to conduct counterterrorism when there’s a stable government in place,” Mr. Carter said. “That circumstance obviously doesn’t exist in Yemen.”

Mr. Carter’s comments, which came during a news conference with his Japanese counterpart during a visit to Tokyo, are a tacit acknowledgement of the complications that have arisen since the start of the military offensive led by Saudi Arabia against the Houthi rebels in Yemen two weeks ago. The Houthis, whom the Saudis have portrayed as Iranian proxies, have taken the capital and driven out the president.

Saudi officials have maintained that their military action is aimed at driving the Houthis, from northern Yemen, out of territory they had captured in the past eight months and restoring Yemen’s exiled president, Abdu Rabbu Mansour Hadi, to power.

Thus far the United States has backed the Saudi effort; Mr. Carter said on Wednesday that the United States was expediting deliveries of weapons to Saudi Arabia, echoing similar promises made the day before in Riyadh by Antony J. Blinken, the deputy secretary of state. “We are providing them with intelligence” and surveillance, Mr. Carter said, “and with some resupply of equipment and munitions.” He said that he had spoken with the Saudi minister of defense the day before to reiterate American support for the Saudi effort in Yemen.

But that effort also has come with consequences, not least of which is an even more resurgent Al Qaeda in the Arabian Peninsula, which has used the breathing room provided by the Saudi assault on the Houthis — foes of A.Q.A.P. — to take territory.

The Houthis captured the capital, Sana, in September, and have since defended their military actions as part of an effort to overturn a corrupt political order in Yemen. The Houthis, who are allied with forces loyal to Yemen’s former autocratic president, Ali Abdullah Saleh, have so far seemed undeterred by the Saudi air campaign.

The fighting and the airstrikes have led to widespread civilian suffering in Yemen, the Middle East’s poorest country, and have bought warnings from international relief agencies that a humanitarian disaster is unfolding. More than 540 people have been killed and 1,700 wounded by the fighting since March 19, an official with the World Health Organization told reporters in Geneva on Tuesday.

The turmoil in Yemen has also upended the Obama administration’s counterterrorism efforts there. Last month, before the Saudis intervened, the United States evacuated 125 Special Operations advisers from Yemen amid the fighting, dealing a significant setback to American counterterrorism intelligence-gathering in a crucial country. Since then, the situation in Yemen has become even more precarious.

Mr. Carter was in Japan for the first stop of his first trip to the Asia-Pacific region as the new secretary of defense and had scheduled a series of meetings with the Japanese that were designed to showcase the Obama administration’s much talked-about pivot to Asia. But, as has been the case just about every time a senior American official has traveled to Asia to talk up those plans, turmoil in the Middle East again demonstrated that that region was not yielding the stage anytime soon, no matter what senior Obama administration officials have hoped.

Nonetheless, Mr. Carter carried on with his meetings on new guidelines to govern the long-running military alliance between the United States and Japan, meant to help counter a newly assertive China.