  Proceeding from close association between solar eruptions, flares, shock
waves, and CMEs, we analyze relations between bursts at 35 GHz recorded with
the Nobeyama Radio Polarimeters during 1990-2012, on the one hand, and solar
energetic particle (SEP) events, on the other hand. Most west to moderately
east solar events with strong bursts at 35 GHz produced near-Earth proton
enhancements of J(E > 100 MeV) > 1 pfu. The strongest and hardest those caused
ground level enhancements. There is a general, although scattered,
correspondence between proton enhancements and peak fluxes at 35 GHz,
especially pronounced if the 35 GHz flux exceeds 10^4 sfu and the microwave
peak frequency is high. These properties indicate emission from numerous
high-energy electrons in very strong magnetic fields suggesting a high rate of
energy release in the flare-CME formation process. Flaring above the sunspot
umbrae appears to be typical of such events. Irrespective of the origin of
SEPs, these circumstances demonstrate significant diagnostic potential of
high-frequency microwave bursts and sunspot-associated flares for space weather
forecasting. Strong prolonged bursts at 35 GHz promptly alert to hazardous SEP
events with hard spectra. A few exceptional events with moderate bursts at 35
GHz and strong proton fluxes look challenging and should be investigated.
