US invade Plaza de la Cultura?

This morning I took a friend who is visiting the DR to Plaza de la Cultura in Santo Domingo. When I parked the car a security guard told me that the car park had been rented by the US Embassy and that I could not park there. I looked around and indeed some - but not all - of the vehicles had diplomatic plates. There were no signs or barriers so I insisted that this was Plaza de la Cultura and that I was entitled to park there. He then backtracked and said that I could leave my car there but that as he was an Embassy security guard he could not be made responsible for its safety. Although the conversation was fairly amicable I felt this came across like a veiled threat.

I left the car there and asked the people in the Museo de Arte Moderno what was going on: their reply was that the car park was part of the Plaza de la Cultura complex I was perfectly entitled to park there. When I got back the car was fine and the guard greeted me - so what was all that about?

If there is anyone reading this connected with the Embassy who knows what the situation is I would welcome a clarification.

By the way, the current exhibitions at the Museo de Arte Moderno are highly recommended. The Museo de Historia is a bit ragged at the edges and when we tried to visit the exhibition room which includes relics of the Trujillo years we were told the man with the key was at lunch...

All in all a day of mixed impressions for my tourist friend.

Chiri