The project would have built on the ruins of the defence ministry bombed by Nato back in 1999.
The president's son-in-law wants to build a hotel on the ruins of the former Yugoslav Army headquarters.
President Aleksandar Vucic - populist and close to Russia - has faced months of protests and alleges a foreign coup plot.
The Serbian project, led by Trump's son-in-law Jared Kushner, has run into opposition and scandal.
Serbian officials have denied allegations security forces deployed a military-grade Long Range Acoustic Device.
The collapse of a station canopy that killed 15 people has galvanised anger towards the government.
Police gather evidence against MPs who let off smoke bombs and flares in a protest over claims of corruption.
Milos Vucevic's resignation follows months of nationwide demonstrations over the collapse of a station roof which killed 15.
Vladimir Kecmanoviæ and Miljana Kecmanoviæ will serve jail terms of 14 and three years respectively.
