SIMFEROPOL, Ukraine (AP) — Ukraine's largest bank says customers in the nation's Crimean Peninsula are lining up to withdraw cash from their accounts as the region occupied by Russian troops prepares for Sunday's referendum on joining Russia.

Lines of customers could be seen forming on Thursday outside Privat and other banks amid uncertainty over the peninsula's future.

Oleh Serha, a spokesman for Privat bank, said all banks in Crimea are struggling to deliver more cash to the region, where tensions are high between ethnic Russians and minority ethnic Ukrainians and Tartars.

Serha said the bank has imposed a limit of 1,500 hryvna ($150) on daily withdrawals across all of Ukraine.

Its government and Western nations have denounced the referendum as illegitimate and warned Russia against trying to annex Crimea.