Magnetotransport measurements are made in the title compounds under high pressures. An anomalous state is found in the low-temperature-low-field-low-pressure regime in the K-compound while the NH4-one behaves as expected from the current model for quasi two-dimensional electronic systems. The anomalies are found in the so-called angle-dependent oscillation of magnetoresistance and the field and temperature dependence of the resistance. A phase diagram for the K-compound is made experimentally and electronic structures are discussed in relation to the possible spin-density wave found already in the anomalous state.