Israel has implemented a blockade on humanitarian supplies entering Gaza following Hamas's refusal to accept a proposed change to the ceasefire agreement.

Prime Minister Benjamin Netanyahu's office announced on Sunday that all goods and supplies would cease as of that morning, asserting that Israel would not allow a continuation of the ceasefire without the release of hostages.

Netanyahu's statement followed the breakdown of talks in Cairo aimed at extending the ceasefire, which has been in effect for 15 months.

According to the Israeli government, the cessation of aid was prompted by Hamas's refusal to engage with a plan purportedly set forth by U.S. special envoy Steve Witkoff.

This plan was intended to extend the first phase of the ceasefire and facilitate ongoing negotiations for hostages.

In consequence, no trucks delivering aid to Gaza entered the territory on that Sunday morning.

UN Secretary-General António Guterres called for an immediate end to Israel's suspension of humanitarian aid to Gaza.

In a statement denouncing the blockade, Hamas characterized Israel's decision as a 'war crime' and 'a blatant coup against the ceasefire agreement.' They reaffirmed their commitment to the original ceasefire terms, which included provisions for the phased release of hostages and an increase in aid deliveries, while rejecting any suggestions for a temporary extension of the pact.

A senior official from Hamas, Mahmoud Mardawi, reiterated that the group would only release the remaining Israeli hostages in alignment with the previously negotiated terms.

Prior to the ceasefire, UN officials had warned of a potential humanitarian crisis with escalating famine conditions.

Following the initiation of the truce, aid deliveries reportedly returned to levels of approximately 600 trucks per day, primarily consisting of food supplies.

However, stark shortages in drinkable water and medical facilities persist, in tandem with widespread infrastructural devastation exacerbated by the ongoing conflict.

Netanyahu's announcement followed a deadlock in negotiations in Cairo.

His office noted that it had agreed to extend the first phase of the ceasefire through the Ramadan and Passover period, culminating on April 20, which would involve the release of a proportional number of hostages and deceased individuals.

The initial phase of the ceasefire involved mutual hostage exchanges, increased humanitarian aid, and a temporary retreat of Israeli forces.

The anticipated second phase requires a full Israeli withdrawal and a more sustainable cessation of hostilities.

Reports indicate that the newly proposed plan, as delineated by Netanyahu's office, lacks specific provisions for the troop withdrawal stipulated in the original agreement.

Political analysts in Israel have suggested that Netanyahu's acceptance of the ceasefire was influenced by external pressures, particularly from former U.S. President Donald Trump, and that negotiations for a second phase were not advanced under his government.

The Israeli finance minister, Bezalel Smotrich, and national security minister, Itamar Ben Gvir, both publicly supported the cessation of humanitarian aid, framing it as a necessary step until all hostages are returned.

Smotrich's remarks included a call for a more aggressive military response.

Amid the blockade, reports from Gaza indicate ongoing violence, including a recent incident in which Israeli airstrikes resulted in Palestinian casualties.

Since the ceasefire was established, the Gaza conflict has led to thousands of Palestinian deaths and injuries, according to local health authorities.

Previous agreements negotiated with the involvement of U.S., Egyptian, and Qatari officials have outlined a three-phase ceasefire plan, each lasting 42 days.

However, breaches of the humanitarian protocol by Israel have continued to be reported, with incidents of military incursions and other forms of aggression ongoing, despite the truce.