Switzerland gathered diplomats from 126 of the 196 signatories of the Geneva Conventions to discuss protections for civilians, fulfilling a five-year-old request for such a conference from the UN General Assembly.
But the United States and Israel shunned the talks, held amid mounting tensions between Palestinians and Israelis, warning that the event threatened Switzerland's role as neutral arbiter.
The conference ended in a ten-point declaration condemning Israel's actions in the occupied territories and also reminding both sides of the protracted conflict of their obligations to protect civilians.
Paul Fivat, Switzerland's special ambassador for the Geneva Conventions, said the intention was "not to accuse, it was not a tribunal.. it was a place simply for the parties to reiterate what is international law".
"This declaration is a signal that is being sent to conflicting parties, especially the civilian populations, that there is a law which is protecting their interests," he told reporters.
But the Israeli foreign ministry said the talks undermined international law and "confers legitimacy on terrorist organizations and dictatorial regimes wherever they are".
"The conference convened today in Geneva was a political exercise, lacking any basis in the Geneva Conventions," the ministry said in a statement.
It added: "It won't stop Israel from implementing its primary obligation to its citizens — to provide them with security and protect them from merciless and fanatic terrorists (who) do not hide their desire to see Israel wiped off the map of the Middle East."
The US also boycotted the conference, saying that it "risks politicizing the Geneva Conventions".
Fivat took pains to stress that the conference was held in response to a 2009 recommendation from the UN General Assembly at the request of Palestinian authorities, and that all signatories of the Conventions were invited.
Initial consultations on a conference were suspended in 2011 before being re-launched in July.
The Palestinian envoy to the UN Human Rights Council, Ibrahim Khraishi, said before the conference that he hoped it would "be helpful to remind the Israelis of their obligations to respect the Geneva Conventions".
The conference, attended by permanent representatives to the UN, focused on the Fourth Convention, which defines humanitarian protections for civilians in a war zone.
The final declaration reiterated the prohibition on all parties from conducting indiscriminate or disproportionate attacks, attacking protected targets such as schools and hospitals, and using civilians as human shields.
It also condemned Israel's towering concrete separation barrier that runs deep inside the West Bank, as well as Jewish settlements and the blockade of the Gaza Strip.