Ratings agency Standard & Poor's says Venezuela has defaulted on its debt after it failed to make payments due on some of its bonds.

The agency said Tuesday it was downgrading Venezuela's sovereign debt grade to SD — short for "selective default," which means the country decided to skip a payment on a specific bond but is overall still committed to honoring its international debts. Previously it had Venezuela in junk bond status.

S&P said Venezuela had failed to make $200 million in coupon payments for bonds due 2019 and 2024 within the allowed 30-day grace period.

The agency says "there is a one-in-two chance that Venezuela could default again within the next three months."