(Adds details, industry background)
By Jessica Jaganathan
SINGAPORE March 19 (Reuters) - Exxon Mobil Corp's Papua New Guinea liquefied natural gas (LNG) export plant has sold a cargo for loading in April at close to $4 per million British thermal units (mmBtu), four industry sources said on Thursday.
The 4.05 trillion British thermal unit (TBtu) cargo is for loading on April 25, they added.
Details of the buyer could not immediately be confirmed and companies typically do not comment on spot trades.
The cargo sold by the Papua New Guinea plant is a jump of almost 40 cents per mmBtu, or about 11%, from a deal concluded in Singapore on Tuesday, traders said.
Commodities trader Vitol sold a 3.3-3.5 TBtu cargo to Diamond Gas International at $3.60 per mmBtu on Tuesday during price agency S&P Global Platt's pricing process known as market-on-close, according to Platts data.
Bigger cargoes typically command a premium, trade sources said, indicating the latest deal does not necessarily reflect a big jump in prices.
But overall demand from China, the world's second-largest LNG importer, is improving, which could stoke spot prices, traders said.
Reporting by Jessica Jaganathan; Editing by Christian Schmollinger and Kenneth Maxwell