Engagement with objects by USAF aircraft

I was in the USAF stationed at a base in Alaska.  I flew F-16's for quite a few years.  It was the last year of the Cold War and the Soviet Union was having problems and starting to fall apart.  They had increased the number of flights per month,, when Soviet bombers would test our early warning systems.It was not uncommon to be sent up to intercept and turn around Soviet aircraft.  During February 1990, there were an unusually high number of alerts that fighters were sent up to investigate and turn back.  But, pilots were returning and reporting they had not found any craft in the area.   
One day mid February, I was one of the pilots on ready status and was scrambled to go intercept several targets.  When we located them, they were holding position, hovering.  We flew past 3 objects at approx 800 meters distance.  They looked like large barrels.  Maybe 3 times the size of a 50 gallon drum.  
My wing man made a flat turn to the South with the intention of creating a separation between us I did a reversal called an Immelmann to create an altitude separation as well.  As I completed it, the objects were no longer visible.  We both continued South searching for them visually and electronically.  After half a minute the other pilot saw the objects on radar diving from extremely high altitude.  They dropped to a couple hundred meters above the ground.  Stopped instantly and held their position.  He was 5,000 ft below me, so he dove towards them.  All 3 objects shot straight up at approx. mach 6 until they went beyond our capabilities to maintain contact.  We patrolled the area for several minutes.  And we began the trip back to base.
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Witness indicates that the date of the sighting is approximate.  PD)