The single chamber of the Mauritanian Parliament, which has 157 seats, called on "brotherly, Arab, African and Islamic parliaments and those of friendly countries in the world to take all measures to help protect the Palestinian people and defend their just cause.”
The Mauritanian legislators also lauded what they called the "resounding victory achieved by the Palestinian resistance against the Zionist enemy", which they said was "the inescapable crowning achievement of its struggle against the occupation".
"The national assembly considers the ongoing Zionist aggression against the Palestinian people as one of the worst crimes of genocide," read the resolution.
It added that the International Criminal Court (ICC) based in The Hague must "prosecute those involved in this aggression".
The resolution, which has symbolic value and is not binding on the government, was passed three days after a large march in support of the Palestinians, organised by the political parties and national NGOs. Fundraising campaigns for the reconstruction of Gaza are also ongoing.
Mauritania, a majority-Muslim nation of 4.5 million people, became in 1999 only the third member of the 22-member Arab League - after Jordan and Egypt - to recognise Israel. It then broke off diplomatic relations in 2009 following Israel’s bombardment of Gaza that year.
Outgoing officials in the Trump administration claimed in January that the West African nation was "weeks" away from finalising a deal to normalise relations with Israel.
The ICC had already opened an investigation in March into possible war crimes in the Palestinian Territories by both Israeli forces and Palestinian armed groups since 2014.
The move infuriated Israel which is not a member of the court, while Palestine has been a state party to the ICC since 2015.
Last week, outgoing ICC Chief Prosecutor Fatou Bensouda said that she noted with "great concern the escalation of violence" in the West Bank and Gaza "and the possible commission of crimes under the Rome Statute," which founded the ICC.