Mediator Qatar announced early Monday that an agreement has been reached to release an Israeli civilian hostage and allow Palestinians to return to northern Gaza, easing the first major crisis of the fragile ceasefire between Israel and Hamas.

A ceasefire in the Gaza Strip took effect on Sunday as Hamas released the first three female hostages it held for 15 months of the devastating war with Israel.

The Israeli cabinet still has to ratify the deal, and some details remained unresolved. President Biden said hostages were to be released over 42 days.

Tens of thousands of Palestinians streamed into the most heavily destroyed part of the Gaza Strip on Monday as Israel lifted its closure.

Under Israel's multi-phased deal with Hamas, some hostages held in the Gaza Strip and Palestinian prisoners in Israeli jails have started to be released. Negotiations between Israel and Hamas are expected to continue amid the first phase of the deal,

Israel has said the next release of hostages will take place on Thursday, followed by another on Saturday. The ceasefire is aimed at winding down the deadliest and most destructive war ever fought between Israel and Hamas and securing the release of dozens of hostages captured in the militants’ Oct.