Nigerian police on Friday said some citizens frustrated by cash shortages in the country were attacking banks and vandalising cash-dispensing machines, and warned that they would be treated as armed robbers.

Association of Senior Staff of Banks, Insurance and Financial Institutions (ASSBIFI) said its members would stay away from work in states where bank branches were being attacked "until normalcy is restored."

Ahead of next week's election to choose new lawmakers and a successor to President Muhammadu Buhari, frustration is rising in Africa's most populous nation over a central bank plan to swap old naira bank notes for new ones. The move has caused shortages of cash and disrupted trade.

On Friday angry customers in Lagos and other states in southern Nigeria attacked banks and burned tyres on the streets to protest failure to access their money, local television showed.

Nigeria Police Force national spokesperson Olumuyiwa Adejobi warned such actions would elicit a strong response from law enforcement agents and those caught should not claim that their rights were being violated.

"Let us get this straight, it's not a peaceful protest when you are coming out and attacking ATMs (automated teller machines), attacking banks or any financial institution. It is robbery and we will treat you like an armed robber," he said in a statement.

ASSBIFI said the union had requested the government to provide security within and around banks, "but regrettably the attacks have continued."

Cash is the main medium of transaction in Africa's largest economy, which is largely informal.

Some politicians have criticised the timing ahead of the Feb. 25 vote, as campaigns are funded by mostly hard-to-trace cash.

On Thursday, Buhari defended the cash swap plan, but authorised the central bank to extend the deadline to turn in old banknotes by another 60 days.

Reuters