In counties where no police department has been established and the sheriff is the chief law-enforcement officer, the sheriff may enter into agreements with any other governmental entity providing law-enforcement services in the Commonwealth, and may furnish and receive interjurisdictional law-enforcement assistance for all law-enforcement purposes, including those described in this chapter, and for purposes of Chapter 3.2 (§ 44-146.13 et seq.) of Title 44. Sheriffs and their deputies, providing or receiving such assistance, shall have all the authority, benefits, immunity from liability and exemptions from laws, ordinances and regulations as officers acting within their own jurisdictions.