On December 30, 1981, the United States brought this action in federal district court in Arizona to enjoin the Tribe from interfering, through its Tribal Court or otherwise, with any officers of the United States in the performance of their official duties, including the preparation and filing of water rights claims in W-1.

In the meantime, the United States began its own challenge to state court jurisdiction over adjudication of Indian water rights in W-1, as well as to the adequacy of the state procedures for adjudication of the issues involved. In January 1982, the government moved to dismiss itself from W-1. A separate challenge to state court jurisdiction was filed in U.S. District Court by various parties. See In re Determination of Conflicting Rights to the Use of Water from the Salt River Above Granite Reef Dam, 484 F. Supp. 778 (D.Ariz.1980), rev'd, 668 F.2d 1093 (9th Cir.1982), reinstated, 463 U.S. 545, 103 S. Ct. 3201, 77 L. Ed. 2d 837 (1983). Notwithstanding the congressional waiver of sovereign immunity by the McCarran Amendment, 43 U.S.C. Sec. 666,3 some question remained concerning the power of Arizona's courts to determine Indian water rights. The federal case culminated in the U.S. Supreme Court decision in Arizona v. San Carlos Apache Tribe, 463 U.S. 545, 103 S. Ct. 3201, 77 L. Ed. 2d 837 (1983), which held that the McCarran Amendment removed any limitation on state court jurisdiction over Indian water rights that might have been imposed by statehood Enabling Acts or general federal Indian policy. Id. at 563-64, 103 S.Ct. at 3211-12. During pendency of the San Carlos appeal, proceedings in W-1 and the case at bar were stayed.4

Following the Supreme Court's decision in San Carlos and this court's subsequent decision in Northern Cheyenne Tribe v. Adsit, 721 F.2d 1187 (9th Cir.1983),5 proceedings in the instant case began again in the district court. In February 1985, the court granted the government's motion for summary judgment, United States v. White Mountain Apache Tribe, 604 F. Supp. 464 (D.Ariz.1985), and permanently enjoined the Tribe from interfering with officers, contractors or other representatives of the United States in the performance of their official duties, on or off the Fort Apache Reservation, which relate in any way to the preparation and filing of water rights claims in W-1.6 The Tribe appealed, claiming, as it has in all related proceedings, that the government, or its officials, had committed fraud on the Tribe by grossly understating the Tribe's legitimate water claim and had mismanaged the Tribe's valuable water resources through its participation in W-1 and otherwise. And as in the past, the Tribe "denie[d] jurisdiction in the State Court W-1 Proceedings over its reserved rights [to Salt River water]."

Because we find the Tribe had neither the jurisdiction nor the right to interfere with the official conduct of federal business by federal agents or employees, we affirm.

The Tribe asserts here that the state courts cannot adjudicate the water rights claim because the Tribe's dispute with the Department of the Interior over its management of the Tribe's water resources is still unresolved.7 The Tribe contends that the Tribal Court consequently was justified in enjoining specific "subordinate employees" of the Interior Department from assisting with the W-1 litigation. Because only subordinate government employees were subject to the Tribal Court order, the Tribe contends that the order was not directed to the United States or the Department of Justice and so did not bar government participation in W-18 or otherwise improperly restrict the sovereign United States. We cannot agree.

The Tribe's effort to enjoin the work of any federal agent or employee in the performance of his official duties is beyond dispute an action taken against the United States itself. See Dugan v. Rank, 372 U.S. 609, 620, 83 S. Ct. 999, 1006, 10 L. Ed. 2d 15 (1963). Congress has not consented to such a suit. The district court was therefore correct in ruling that the action was barred by sovereign immunity. See Larson v. Domestic and Foreign Commerce Corp., 337 U.S. 682, 688-89, 69 S. Ct. 1457, 1460-61, 93 L. Ed. 1628 (1949).

The Tribe's own sovereignty does not extend to preventing the federal government from exercising its superior sovereign powers. See San Carlos, 463 U.S. at 571, 103 S.Ct. at 3215 ("tribes retain ... their historical sovereignty not 'inconsistent with the overriding interests of the National Government.' ") (quoting Washington v. Confederated Tribes, 447 U.S. 134, 153, 100 S. Ct. 2069, 2081, 65 L. Ed. 2d 10 (1980)). The district court was accordingly correct in concluding that the Tribe was without authority to restrict federal officials in their conduct of official business on the Reservation. United States v. White Mountain Apache Tribe, 604 F. Supp. at 466; see also United States v. Blackfeet Tribe, 369 F. Supp. 562, 564-65 (D.Mont.1973); United States v. Blackfeet Tribe, 364 F. Supp. 192, 194-95 (D.Mont.1973). This conclusion holds regardless of the merits of the Tribe's charges that the officials were conducting their official business improperly.

We likewise reject the Tribe's contention that, because the water rights claim filed by the government on the Tribe's behalf is "fraudulent," the employees covered by the Tribal Court injunction were not acting within the scope of their duties as federal officers. It is now beyond dispute that the state courts of Arizona have jurisdiction to adjudicate the water dispute at issue here. San Carlos, 463 U.S. at 566-70, 103 S.Ct. at 3213-15; Northern Cheyenne Tribe, 721 F.2d at 1188; United States v. Superior Court in and for Maricopa County, 144 Ariz. 265, 697 P.2d 658 (1985); see also 43 U.S.C. Sec. 666; White Mountain Apache Tribe v. Hodel, 784 F.2d 921 (9th Cir.1986). It is also clear that the federal government, as trustee for the tribes, is under an affirmative obligation to assert water claims on its beneficiaries' behalf. The fact that the Tribe does not believe the claim the government has submitted for the Tribe is in all respects proper neither divests the Arizona courts of jurisdiction nor absolves the United States of its responsibility as trustee to assert the claim it believes appropriate.9 Only Congress, not the Tribe, can end the trust relationship. Joint Tribal Council of the Passamaquoddy Tribe v. Morton, 528 F.2d 370, 380 (1st Cir.1975).

Because the United States remains under a continuing obligation to present the Tribe's claim, it is clear that efforts by government agents or employees to prepare the claim are official duties. See Armstrong v. United States, 306 F.2d 520, 522 (10th Cir.1962). The Tribe consequently cannot thwart those official efforts. The district court had jurisdiction to determine the limits of the Tribe's power. National Farmers Union Ins. Co. v. Crow Tribe, --- U.S. ----, 105 S. Ct. 2447, 2452, 85 L. Ed. 2d 818 (1985).10 It properly concluded that the Tribe was without power and enjoined the Tribe's efforts to impede the federal government's work related to W-1.

AFFIRMED.