Opposition lawmakers have heckled South African President Jacob Zuma during a parliamentary session in which questions were raised about more than $20 million in state spending on the president's private home.

Members of an opposition party, the Economic Freedom Fighters, chanted "Pay back the money!" on Thursday after Zuma was questioned about the scandal over his rural Nkandla residence. The uproar forced parliament to suspend the session.

In March, South Africa's state watchdog agency released a report concluding that Zuma inappropriately benefited from state funding and should pay back some money for alleged security upgrades at the president's rural Nkandla residence.

Zuma says he has delivered a response to the parliamentary speaker about the spending at his home, but has yet to say whether he will pay back any money.