PetroChina Group, the country's largest oil and gas explorer, reported an 8 percent drop in its net profit to 36.017 billion yuan ($5.73 billion) for the first quarter compared with the same period last year.

For the first three months, the company produced 231 million barrels of crude oil, up 1.8 percent and 745.3 billion cubic feet of natural gas, up 4.8 percent over the same period of last year, according to the company's statement released on Thursday.

Affected by the drop in international crude oil prices, the operational profit of PetroChina's exploration and production segment had a year-on-year decline of 5.6 percent to 56.983 billion yuan for the first quarter.