Counter-terrorism authorities are said to be hunting for a 16-year-old boy from northern Yemen suspected of having been recruited by Al Qaeda to be a homicide bomber at one of five foreign targets in the southern port city of Aden, according to Western sources close to Yemeni security officials.

Yemeni officials also believe that several members of Al Qaeda in the Arabian Peninsula, the wing of Al Qaeda that operates in Yemen and Saudi Arabia, have entered Yemen in the past few days, and that a key terror group official still is hiding in Abyan, a Yemeni province in southern Yemen. Abyan is the former home of the Aden-Abyan Islamic Army, a group of Islamic militants who were active in the late 1990s and are believed to have been involved in the bombing of the USS Cole in Aden in 2000.

The intelligence reports that have circulated in the past week have caused several Western institutions to quietly shut their offices in Aden and prompted families with children based there to leave, the sources said. There are believed to be only a few hundred Westerners still living in Aden. Yemeni police and security authorities are said to have erected roadblocks to check on travelers.

The intensified threat in Aden comes at a time when the northern-based Yemeni government is not only battling a Shiite rebellion in the north but also a secessionist threat in the south. Regional experts fear that Al Qaeda may be trying to make common cause with those secessionist elements and enhance their appeal in what once was a separate country, South Yemen, whose capital was Aden.

News of a terrorist threat in Aden, previously regarded as the more stable part of the country, came as American and British officials reopened their embassies in Sana’a, the Yemeni capital. Both countries recently shut their embassies for two days, citing terrorist threats by Al Qaeda.

The Westerners close to Yemeni security officials said that the information about the existence of a 16-year-old homicide bomber came from interrogations of Islamic militants captured in late December following joint Yemeni-American air attacks on Dec. 17 in Abyan and Shabwa provinces. The Yemeni government said that over 60 militants were killed in the attacks, but local sources have claimed that the air strikes killed mostly civilians, including women and children.

In an interview Saturday, Yemen’s foreign minister, Abu Bakr al Qirbi, told a reporter from The National, an Abu-Dhabi-based English language newspaper, that Al Qaeda remained “a serious threat to Yemen’s security,” and that Yemen had carried out its strikes to stop Al Qaeda from continuing to operate training camps in his country and making Yemen “a stronghold for their activities.” Al Qirbi said it was hard to estimate how many militants were now operating in Yemen, adding that it could be as many as 300. “It is important to prevent Al Qaeda from recruiting,” he said.

Umar Farouk Abdulmuttalab, the 23-year old Nigerian accused of trying to blow up a Detroit-bound Northwest Airlines plane from Africa through Amsterdam on Christmas Day, has told U.S. investigators that he received training and instructions from Al Qaeda operatives in Yemen. Abdulmuttalab was in Yemen from Aug. 4 to Dec. 7, supposedly studying at the Sana’a Institute for the Arabic Language. Al Qaeda in Yemen announced last week that it had trained Abdulmuttalab, claiming responsibility for the failed bombing in retaliation for the Yemeni government’s American-supported raids.

American officials recently announced that the U.S. would spend $70 million dollars to fund anti-terrorism activities in Yemen, a huge increase in foreign assistance to a country that Washington had largely ignored for years.

Yemeni police said that their security forces, under heavy American pressure to move against Islamic extremists, had captured a key Al Qaeda leader they said had prompted the U.S. and British embassies to close their missions temporarily. The police identified the man as Mohammed al-Hanq, who they said had evaded arrest Monday during a security force raid in Arhab, about 25 miles north of Sana’a. Two of al-Hanq’s relatives were said to have been killed, and three other people were wounded.

The state-run news agency Saba said that al Hanq, a regional leader of Al Qaeda, was arrested Wednesday, along with two others who were wounded in an attack at a hospital in the province of Amran, north of Sana’a. American officials were quoted as saying that the “successful” security operations north of the capital had enabled the threat level to be reduced and the embassy to reopen on Tuesday.

Yemen's interior ministry has said that diplomatic mission in Yemen were “safe” thanks to the increased security measures at embassies and diplomatic residences and the arrests of five "terrorist elements" during the past two days near Sana’a. It provided no further details and did not mention the new threat in Aden.

The deteriorating security situation in Yemen led President Obama to announce that no Yemeni prisoners currently being held at Guantanamo Bay military prison would be released to their homeland for an unspecified time. About 40 of 90 Yemeni prisoners being held there were said to have been cleared for release.

The administration also has added Yemen to the list of 14 countries whose nationals will be required to undergo compulsory enhanced screening when they fly to the United States.

Judith Miller, a Fox News contributor, is an award-winning writer and author, and an adjunct fellow at the Manhattan Institute. The author of several books, her latest is "The Story: A Reporter's Journey" (Simon & Schuster, April 7, 2015) now available in paperback. Follow her on Twitter @JMFreeSpeech.