PetroChina (HKG:0857, SHA:601857) advised Mongolian oil company Petro Matad to cease delivery of Block XX production, saying internal discussions at its head office remain unresolved and its storage tanks in Block XIX are near capacity.

PetroChina's Mongolia subsidiary said it cannot process Petro Matad's invoices until those discussions conclude, according to a Tuesday news release by Petro Matad.

With Chinese national day holidays approaching and oil imports from Mongolia suspended, Petro Matad has shut down its Heron-1 and Gazelle-1 wells.