he flight tests of the ground launched R-16U were conducted from 10 October 1961 through February 1962. The flight tests of the silo launched version began in January, 1962. The first surface-launched missile firing was conducted on 13 July1962, and this version was initially deployed on 15 June 1963. The silo launched version became operational on 15 July 1963 (simultaneously with the R-12U and R-14U missiles). The first three ground based R-16 regiments were put on alert on 1 November 1961, while the first regiment with silo based P-16U missiles was put on alert on 5 February 1963. The system was deployed in both soft and hard sites. In August 1960, the construction of the two surface pads for R-16 missile started in Plesetsk. The new unit commanded by Colonel D.T. Gusha arrived in Plesetsk on June 13, 1961. The 1st Division of the unit was declared battle ready on October 27, 1961 with pads N° 5 and N° 6 operational. The 2nd Division had been officially ready to launch R-16 missiles from pads N° 7 and N° 8 since January 15, 1962. At the same time, three silos for R-16U missile were under construction in Plesetsk.   Between 1961 and 1965 a total of 186 mostly surface-based R-16 and R-16U were  deployed. On March 30, 1963, three silo-based launchers NN° 9, 10 and 11 for R-16U missiles were officially introduced in Plesetsk. The newest of the silos, N° 11, became the core of war games under code-name "Groza" ("Thunder") orchestrated from Moscow, apparently, in the wake of Cuban missile crisis.