DOHA/CAIRO/GAZA (Reuters) -Israeli forces killed at least 14 Palestinians in airstrikes as they pressed their onslaught in Gaza's main southern city Khan Younis on Tuesday, while the top U.S. diplomat pursued a quest to broker a ceasefire in the four-month-old war. Israel said its forces had killed dozens of Palestinian gunmen throughout Gaza in the past 24 hours with fighting focused on Khan Younis in the south and a threatened assault looming on a nearby border town teeming with displaced people. U.S. Secretary of State Antony Blinken arrived in Egypt for talks after a stop in Saudi Arabia during his latest trouble-shooting Middle East swing that Palestinians hope will nail down a ceasefire before Israeli forces storm Gaza's southern fringes where over a million of Gaza's people are sheltering.