Solvation force and phase behavior of water confined between hydrophobic surfaces at nanoscale distances have been studied by molecular dynamics simulation of the TIP4P model water. Freezing and melting of confined water are observed at certain intersurface separations in bringing one surface to the other at a fixed temperature and a fixed lateral or bulk pressure. Solvation force curves are found to be discontinuous upon freezing and melting of confined water and exhibit strong hystereses, implying a peculiar manifestation of the hydrophobic effect. The thermodynamics for a confined system at fixed surface separation, temperature, and lateral or bulk pressure is applied for examining the liquid-solid equilibria of confined water.