Hamas formally responded on Tuesday to a U.S. ceasefire proposal outlined by U.S. President Joe Biden on May 31 that envisages a ceasefire and phased release of Israeli hostages in Gaza in exchange for Palestinians jailed in Israel, ultimately leading to a permanent end to the war.

"Hamas could have answered with a single word: Yes," Blinken said at a news conference in Doha.

"Instead, Hamas waited nearly two weeks and then proposed more changes, a number of which go beyond positions that it had previously taken and accepted."

A Hamas official told Reuters the response reaffirmed its stance that a ceasefire must lead to a permanent end to hostilities in Gaza, withdrawal of Israeli forces, reconstruction of the Palestinian enclave and release of Palestinian prisoners in Israel.

Blinken said some of Hamas's counterproposals were "workable" and that he believes the gaps that remain between the two sides can be bridged.

Negotiators from the U.S., Egypt and Qatar have been trying for months to mediate a ceasefire and free the hostages, more than 100 of whom are believed to remain captive in Gaza.

"But in the days ahead, we are going to continue to push on an urgent basis with our partners with Qatar, with Egypt, to try to close this deal," Blinken said.

"We're determined to try to bridge the gaps, and I believe those gaps are bridgeable. Doesn't mean they will be bridged because again, it ultimately depends on people saying yes," he added.

More than 1,200 people were killed and over 250 taken hostage by Hamas on Oct. 7, according to Israeli tallies. More than 100 hostages are believed to remain captive in Gaza.

Israel launched an air, ground and sea assault on the Palestinian territory, killing more than 37,000 Palestinians, according to Gaza health authorities.