Nicaragua, a longstanding supporter of the Palestinian cause, is broadening the legal battle over the Gaza conflict at the International Court of Justice by bringing a case against Germany, a major supplier of arms to Israel.

Nicaragua is arguing in its filing that “Germany is facilitating the commission of genocide” in Gaza and violating the Genocide Convention by providing Israel with military and financial aid. It asks for emergency measures ordering Berlin to halt its wartime support to Israel.

In hearings opening on Monday at the court in The Hague, Nicaragua is also expected to assert that Germany is enabling grave breaches of the Geneva Conventions by Israel, in particular the obligation to protect civilians during armed conflict.

The case brought by Nicaragua raises new questions about the liability of countries that have supplied weapons to Israel for the war in Gaza.

Lawyers say that Germany — Israel’s second-largest arms provider, after the United States — is an easier target for a suit than is the United States. Germany has granted full jurisdiction to the International Court of Justice, the United Nations’ highest court. But the United States denies its jurisdiction, except in cases where Washington explicitly gives its consent.

Nicaragua’s case is the third before the court this year that deals with the Israeli-Palestinian conflict.

South Africa first sought emergency measures from the court, arguing that Israel was at risk of committing genocide, an assertion that the court found plausible but that Israel has strongly denied. The court ordered Israel to ensure that its citizens and soldiers do not violate the Genocide Convention, which Israel has signed. The convention forbids actions intended to destroy, in whole or in part, a national, ethnic, racial or religious group.

South Africa has also petitioned the I.C.J. about hunger in Gaza and obtained a new ruling ordering Israel to permit delivery of food, water and other vital supplies “without delay.” Despite the court’s authority it does not have any means of forcing Israel to comply with its orders. Israel has strongly denied accusations of deliberate starvation in Gaza.

In February, the court also took up a case requested by the United Nations General Assembly on the legality of Israel’s occupation of Palestinian territories. Those hearings, planned long before the war, heard from more than 50 countries, most of which vented anger and frustration at Israel’s attacks on Gaza and the worsening death toll among civilians, many of them children.

The Nicaraguan case is far broader in scope than South Africa’s, invoking both violations of the Geneva Conventions and the convention against genocide, and requiring the protection of civilians. It also accuses Israel of other “unlawful” conduct in the occupied territories.

The court has not yet accepted the case, but it is obliged to react quickly to requests for emergency measures, as in this case.

Israel, which is not a party to the dispute between Nicaragua and Germany, will not appear before the court in the hearings this week, which are expected to last two days. Germany is expected to respond to Nicaragua’s case on Tuesday morning.

The recent intense activity at the court has put it in a rare spotlight. Lawyers say that countries have turned to the court because efforts by the United Nations and other negotiators have failed so far to stop the Gaza war.

“The I.C.J. is not going to end the war in Gaza, but it is a diplomatic tool that foreign policy uses to apply additional pressure on Israel,” said Brian Finucane, a senior adviser at the International Crisis Group, a think tank for conflict resolution. “In the Nicaragua case, it further applies pressure on Germany.”

Nicaragua’s government is itself facing sanctions for repressive policies at home. A United Nations special report last month said that the government’s numerous abuses, including the jailing and deportation of opposition figures as well as Roman Catholic clerics, were “tantamount to crimes against humanity.”