The United States, joined by Arab mediators, sought to conclude an agreement between Israel and Hamas to halt the 14-month-old war in the Gaza Strip, where medics said Israeli strikes killed at least 20 Palestinians on Wednesday.

A Palestinian official close to the negotiations said on Wednesday that mediators had narrowed gaps on most of the agreement's clauses. He said Israel had introduced conditions which Hamas rejected but would not elaborate.

On Tuesday, sources close to the talks in Cairo, the Egyptian capital, said an agreement could be signed in coming days on a ceasefire and a release of hostages held in Gaza in return for Palestinian prisoners held by Israel.