Indian law is enforced by a number of agencies. Unlike many federal nations, the constitution of India delegates the maintenance of law and order primarily to the states and territories. At the federal level, some of India's paramilitary forces are part of the Ministry of Home Affairs and support the states. Larger cities have police forces under their respective state police. All senior officers in the state police forces and federal agencies are members of the Indian Police Service (IPS). Central agencies The central agencies are controlled by the central government. Most federal law-enforcement agencies are under the Ministry of Home Affairs. The head of each agency is an IPS officer. The constitution assigns responsibility for maintaining law and order to the states and territories, and almost all routine policing—including the apprehension of criminals—is done by state-level police forces. The constitution also permits the central government to participate in police operations and organization by authorizing the creation of the Indian Police Service. Central police forces can assist a state's police force if requested by a state government. During the 1975–77 Emergency, the constitution was amended on 1 February 1976 to permit the central government to deploy its armed police forces without state permission. The amendment was unpopular, and use of the central police forces was controversial. After the Emergency was lifted, the constitution was again amended in December 1978 to restore the status quo. Ministry of Home Affairs The principal national ministry concerned with law enforcement is the Ministry of Home Affairs (MHA), which supervises a large number of government functions and agencies operated and administered by the central government. The ministry is concerned with matters pertaining to the maintenance of public peace and order, the staffing and administration of the public services, delineation of internal boundaries, and the administration of union territories. In addition to controlling the IPS, the Ministry of Home Affairs maintains several agencies and organizations dealing with police and security. Police in the union territories are under the MHA. The Minister of Home Affairs is the cabinet minister responsible for the ministry; the Home Secretary, an Indian Administrative Service (IAS) officer, is the ministry's administrative head. Central Armed Police Forces Border Security Force The Border Security Force (BSF) is responsible for policing India's land borders in peacetime and preventing trans-border crimes. A central police force under the Ministry of Home Affairs, its duties include VIP security,