During their meeting on the sidelines of the Economic Cooperation Organization summit, Zardari expressed a desire for more collaboration between Pakistan and Iran in trade and investment, and energy to bring their peoples closer, the state-run Associated Press of Pakistan reported.
Zardari called for speedy completion of joint projects such as the multibillion-dollar Iran-Pakistan gas pipeline, electricity transmission lines and rail and road works, the report said.
Pakistani officials attending the meeting included Foreign Minister Hina Rabbani Khar, the report said.
Zardari was quoted as saying greater interaction between the two nations would not only strengthen historical, cultural and religious bonds but help benefit from each other's resources and expertise.
He cited the agreement for Pakistan's export of rice and wheat to Iran, adding it "is a test case for our barter trade and if successful, it can be replicated in other areas."
The gas pipeline between the two neighbors calls for supplying Iranian gas from its South Pars field near the border at 750 million cubic feet a day to Pakistan when the pipeline is commissioned, expected in December 2014.
On Syria, Zardari said Pakistan supported independence, sovereignty and territorial integrity of Syria, APP said.
Ahmadinejad said democracy will not come out of NATO gun barrels or by waging war and fostering armed conflicts, Iran's Press TV reported.
Iran is under tough Western economic sanctions because of its nuclear program and the value of its currency has plunged, causing higher inflation.
Ahmadinejad called for vigilance among regional countries, saying Western countries "have ruled our region for 100 years and intend to continue their domination over the region," the state television report said.