"As" in this context is part of a larger sentence structure; think of this as a common pattern that is used in English. This is also why the present continuous form is used - it's part of the sentence structure. In English, the present continuous structure is for past events which still affect the present.
So in your example, Mr. Singh said (in the past) something which Mr. Jasim is now quoting in the present.
Please let me know if this explanation makes sense or if any additional clarification is needed! If any other forum members can clarify this better than I can, please do!