Supermassive black holes (SMBH) at the center of active galactic nuclei (AGN) are the most massive compact objects in the universe. They offer an excellent laboratory to test the physics of gravity, mass accretion and launching of relativistic jets. High-resolution radio interferometric observations are especially a powerful tool since one can directly resolve and image the immediate vicinity of SMBH for nearby AGN, as represented by the recent BH shadow imaging of M87 with millimeter VLBI. In this talk I will overview some recent observational progress of high-resolution VLBI studies of SMBH and relativistic jets. I will also highlight the recent collaboration and expansion of VLBI facilities in East Asia and relevant AGN studies using these instruments.