The Obama administration plans to reduce U.S. military forces in Europe, but scale back the deeper cuts envisioned under the Bush administration.

A senior U.S. official says the administration plans to remove one of the four deployable combat units known as brigade combat teams currently assigned to Europe. An earlier plan developed by former Secretary of Defense Donald H. Rumsfeld called for removing two units.

The official spoke on condition of anonymity because the Defense Department has not yet made the announcement. The cuts would come mostly in Germany. The plan would remove one of two units currently assigned to Germany in 2015. They are the 170th Brigade Combat Team based in Baumholder and the 172nd Infantry Brigade based in Grafenwoehr. The administration has not decided which unit would be withdrawn, but expects to in coming months.

The European-based units have played major roles in the U.S. operations in Iraq and Afghanistan. In recent years, one or two of the units have been deployed in those operations at any given time, reducing the overall number of troops in Europe. But with plans to end U.S. combat operations in Afghanistan by the end of 2014, troops will be rotating back to Europe and officials say the number of U.S. troops in Europe will be higher than they are now after the 2015 relocation.

However, the relocation and closure of facilities in Germany will reduce the capacity for stationing troops in Europe. Even ahead of the decision, the likely cuts were drawing concerns. Last year, in congressional testimony, NATO's top commander, U.S. Navy Adm. James Stavridis, called for keeping four combat units, saying that anything else would pose risks for his European mission.

In a recent letter to U.S. Secretary of Defense Robert Gates, the senior Republican on the Senate Foreign Relations Committee, Richard Lugar warned that the withdrawals could undermine European security and the sense among NATO allies that the U.S. is committed to Europe.

The planned cutback continues a trend since the end of the Cold War as the security threat from Russia has receded. Between 1989 and 2003, the U.S. Army closed 70 percent of facilities in Europe. Overall, Army troop numbers in Europe have fallen from 213,000 in 1989 to about 42,000 today.