WASHINGTON — Secretary of State John Kerry warned Friday against a further escalation of the conflict in Gaza, while calling on “those who have influence” over Hamas to persuade the terror group to release kidnapped IDF officer Lt. Hadar Goldin. Kerry spoke hours after a Hamas attack on IDF troops near Rafah in southern Gaza, during a US-UN-brokered humanitarian truce, in which two soldiers were killed and Goldin was seized.

Describing the Friday morning attack as an “outrageous violation of the ceasefire,” Kerry called on Hamas to immediately release the captive soldier.

Kerry condemned the attack “in the strongest possible terms,” calling it “an outrageous violation of the ceasefire negotiated over the past several days, and of the assurances given to the United States and the United Nations.”

In a remark related to the role of states like Qatar, a US interlocutor which has been critiqued for its extensive support to Hamas, Kerry called “on those with influence over Hamas to reinforce this message.”

Kerry’s wording echoed comments earlier Friday by White House Spokesman Josh Earnest who said that the White House “would encourage those who have influence with Hamas to get them back on to the terms of a ceasefire and to get them to abide by the agreements that they struck just yesterday.”

Kerry also called for de-escalation of the Israel-Hamas conflict, warning that “it would be a tragedy if this outrageous attack leads to more suffering and loss of life on both sides of this conflict.”

Amid some conflicting reports as to whether Hamas or Islamic Jihad gunmen carried out the operation, Kerry placed blame squarely on the shoulders of Hamas – emphasizing that it “has security control over the Gaza Strip” and calling on Hamas alone to “immediately and unconditionally release the missing Israeli soldier.”

Kerry confirmed that he had discussed the incident with Prime Minister Benjamin Netanyahu, UN Special Coordinator Robert Serry and “other regional partners,” and said that “the international community must now redouble its efforts to end the tunnel and rocket attacks by Hamas terrorists on Israel and the suffering and loss of civilian life.”

Speaking earlier in the morning on CNN, Earnest described Friday’s attack as “a blatant, barbaric violation of the cease-fire agreement” and called on the international community to “respond to this and condemn it in the strongest possible terms.”

Earnest rejected claims that the terms of the ceasefire were unclear, after a Hamas spokesman told the same television channel that he “’didn’t know anything about Israel being allowed to do defensive maneuvers” against terror tunnels linking Gaza to Israel.

“The devil is always in the details of these kinds of agreements. Everybody understands that you have to look very carefully at the details to which you are agreeing,” Earnest emphasized.

“While complicated, we were transparent and everybody, all sides were transparent about what the agreement was, and certainly Hamas, according to these reports, is entirely responsible for upholding their end of the bargain and it’s apparent that they did not do that.”