Spain under Sanchez has infuriated Israel's right-wing government by recognizing a Palestinian state and criticizing Israel's conduct of its war against Hamas.

"If we are telling our people that we are supporting Ukraine because we are defending the international law, this is the same to what we have to do towards Gaza," he said at NATO's 75th anniversary summit in Washington.

The socialist leader said there should be a "consistent political position" in which "we don't have double standards."

Sanchez said the world needed to press to "stop this terrible humanitarian crisis" affecting the Palestinians and called for an international peace conference to push for a Palestinian state.

"We need to create the conditions for an immediate and urgent ceasefire," he said. "There is a real risk of escalation to Lebanon."

Sanchez said he also supported "democracy, freedom and the right to exist of a country such as Ukraine."

NATO leaders at the summit issued a declaration that said Kyiv was on an "irreversible" path to join the alliance.