It was misquote by Sputnik.
The actual transcript was like this:
Ques: What would you like to say about the recent media reports of sale of Su-35 to Pakistan?
Ambassador: "Yes, Pakistan is interested in further expansion of the military-technical cooperation with Russia. But I would not want to limit my answer by the possibility of purchase weapons alone. We attack great importance to the agreement on defense cooperation, which was signed in Islamabad in November 2014 during the visit of the Russian defense minister," Khalilullah said.
Recently our Chief of Staff of the Air Force Air Chief Marshall Sohail Aman visited Russia and held fruitful talks on the matters of defence cooperation.
Pakistan Air Force along with other service would like to deepen cooperation with Russia.
So as you can see he never directly reffered to Su-35.
Also Pakistani Ambassador himself made it clear that Russia will provide only counter terrorism weapons:
http://m.sputniknews.com/world/20160905/1044975268/pakistan-russia-anti-terrorism.html