More than 33,000 reservists have been called to active duty in support of the U.S. buildup in the Persian Gulf area - nearly as many as were activated during crises in Vietnam and Korea.

The Army Thursday activated 12 National Guard and 24 Army Reserve units from 24 states and Puerto Rico, for a total of 4,846 troops. Meanwhile, the Marine Corps said Wednesday it was calling up about 160 reservists.Those actions brought to 33,252 the number of reservists from all services activated since Aug. 22 when President Bush authorized their use in support of Operation Desert Shield.

None of the reserves called so far are from combat units; all are performing combat support or combat service functions such as cargo handling, air, sea and ground transportation, water purification, intelligence and security.

The 160 Marine reservists are the first from that branch to get the call in the current crisis.

The Pentagon said in late August that it expected to call up nearly 50,000 reserves by Oct. 1, but officials recently said the immediate need had been overestimated.

Still, the total ordered to active duty so far is approaching the 35,280 called up in 1968 following the Tet offensive in Vietnam and the seizure by North Korea of the U.S. surveillance ship Pueblo. Those were the most recent uses of military reserves, other than a brief callup during the 1970 postal workers' strike.