The United States, joined by Arab mediators, sought to conclude an agreement between Israel and Hamas to halt the 14-month-old conflict in the Gaza Strip where medics said Israeli strikes killed at least 16 Palestinians overnight, Reuters reports.

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 release of hostages held in Gaza in return for Palestinian prisoners held by Israel.

Medics said an Israeli airstrike killed at least 10 people in a house in the northern town of Beit Lahiya, where army forces have operated since October, while six were killed in separate airstrikes in Gaza City, Nuseirat camp in central areas, and Rafah near the border with Egypt.

There was no immediate comment from the Israeli military spokesman.

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

CIA Director William Burns was due in Doha for talks with Qatari Prime Minister Sheikh Mohammed bin Abdulrahman Al Thani on bridging remaining gaps between Israel and Hamas, other knowledgeable sources said. The CIA declined to comment.