On May 31, Maj. General Sheridan’s cavalry seized the vital crossroads of Old Cold Harbor. The following morning, Sheridan was able to repulse an attempted repossession by Confederate infantry. Confederate reinforcements soon arrived and clashed with the Union Sixth and Eighteenth Corps when they reached Cold Harbor that evening. By June 2, the armies had formed a seven-mile front that extended from Bethesda Church to the Chickahominy River. General Grant was poised for a major assault to General Lee’s right flank and cut off the Confederates off from Richmond, but when Maj. General Hancock's Second Corps arrived after a midnight march too fatigued to support the Union left flank, the operation was postponed until the following day. This fatal delay gave Lee's troops time to build an impressive line of trenches. At dawn June 3, the Union Second, Sixth, and Eighteenth Corps, followed later by the Fifth and Ninth Corps, assaulted along the Bethesda Church-Cold Harbor line and were slaughtered at all points. Grant pulled out of Cold Harbor after nine days of trench warfare and continued to try to flank Lee's army at Petersburg. Grant later expressed remorse for the egregious Union casualties at Cold Harbor, stating, "I have always regretted that the last assault at Cold Harbor was ever made [...] no advantage whatever was gained to compensate for the heavy loss we sustained."