Updated

Terrorist groups in Somalia, North Africa and Nigeria are eyeing ways to coordinate their training, funding and terror activities, triggering increased U.S. national security worries, the top American commander for Africa told Congress on Wednesday.

Army Gen. Carter Ham said terror leaders from al-Shabab, al-Qaida in the Islamic Maghreb and Boko Haram in Nigeria want to more closely synchronize their efforts. If they are able to better share their training and funding, "that presents a real challenge for us," he told the House Armed Services Committee.

The three groups represent the greatest threats to security in the region, and all three have strong ties to al-Qaida. And Ham laid out ongoing efforts by the U.S. to provide training, equipment and support to a number of nations across northern and east Africa where militants have launched a range of dramatic attacks over the past year or more.

Increased U.S.-backed operations around Mogadishu, largely by Ugandan and Burundian troops as part of an African Union force, have weakened al-Shabab. And Ham said the recent announcement of al-Qaida's formal alliance with al-Shabab suggests the Somalia-based insurgency has been weakened and is looking for greater international support.

"It's not quite a last gasp," Ham said, but it indicates that al-Shabab is under duress by the military operations that are working to free swaths of Mogadishu from the insurgents' control.

He added that the formalized merger of al-Shabab and al-Qaida, announced Feb. 9 by al-Qaida leader Ayman al-Zawahri, may allow the groups to focus on threats against American interests.

In other comments, Ham said there are small pockets of foreign fighters who were involved in the resistance in Libya that ended up fighting against U.S. and coalition troops in Iraq. And he said al-Qaida may be trying to re-establish those insurgent networks.

Members of the committee questioned why the headquarters for U.S. Africa Command is in Germany, and why the command has so much fewer resources than U.S. European Command, when much of the emerging threats against America come from Africa.

Ham said the African nations don't necessarily want a big U.S. presence in their countries.

And Navy Adm. James Stravidis, head of U.S. European Command, said it is important to keep a strong presence in Europe because those are the allies America will turn to in a crisis.

The U.S. military is cutting the number of Army combat brigades in Europe from four to two and pulling out two other smaller units — a total reduction of about 12,000 troops. The cuts will leave about 68,000 U.S. forces in Europe, down from a high of about 400,000 at the height of the Cold War.

Stravidis and Ham also told the committee that the forces in Europe can more quickly get to hotspots in the region, including the Middle East, Eastern Europe or Africa. They pointed to last year's Libyan conflict as an example.