I think, even in U.S., the usage varies by regions. In my region, Virginia, many companies use a term "Accounting" for a department that processes bookkeeping, issues financial statements, tracks departmental/project budgets and expenses.
Here, Accounting Department is a place where recording and reporting are performed. For smaller companies, accounting department often does not exist and finance department performs all-things-money.
As to Accounts Department, many companies in my region use that term for a department that is transactional such as sales, Accounts Receivable, and procurement, Accounts Payable, although many companies have AR and AP teams as part of accounting department to track and render transactions that sales/procurement departments report. Sales and procurement employees manage customer accounts and vendor accounts so they often have a job title that includes the word "accounts"--e.g. Accounts Manager.
This is not related to your question but Accounts Management is usually separated from Accounting because it is considered dangerous to have a single person/team to have an authority over all of actions, records, and payment processing for sales/procurement because such power allows a person/team to commit fraud by manipulating prices, invoices/receipts, and payment amounts.