"We should remove all the obstacles from the legitimate point of the views -- or any other obstacles which are there -- to make the relations between our two countries transparent," he told journalists.
The Nuclear Program
The international controversy over Iran's nuclear program is one issue that complicates that relationship.
Islamabad has been under pressure from the United States and other Western governments since the UN's nuclear watchdog confirmed that a black-market network linked to Pakistan's top nuclear scientist, Abdul Qadeer Khan, provided Iran with uranium-enrichment technology.
After meeting with Mottaki today, Aziz said Iran has the right to develop nuclear technology for peaceful purposes and under the guidelines of the International Atomic Energy Agency.
Aziz added that the international dispute over Iran's nuclear program should be settled through dialogue rather than military action.
With those positions enunciated, Mottaki's talks then moved on to details about how trade relations between Iran and Pakistan can be improved.
A top item on the agenda is a proposed multibillion-dollar Iran-Pakistan natural-gas pipeline that could be extended to India. Plans call for a link from Iran's abundant gas reserves to provide India's booming economy with about 150 million cubic meters of natural gas per day for 25 years.
Energy officials from Iran, Pakistan, and India met earlier this week in Islamabad to discuss the plan.
The project is opposed by the United States.
Ahmed Waqar, the permanent secretary at Pakistan's Petroleum Ministry, says Islamabad's decision about whether to go ahead with the proposed pipeline depends upon Pakistan's own needs and interests.
"We need energy," Waqar said. "And Iran is one of [the] sources of energy. And any decision in this regard, I would repeat, has to be taken keeping in view the national interest."
Pakistan and India also have long disputes of their own to resolve before the proposed pipeline can be extended into India from a regional distribution hub in Pakistan.
One dispute is over a coastal strip of marshland between India's Gujarat state and Pakistan's Sindh Province. The exact demarcation of the border there has been disputed by both sides since 1947 when Pakistan and India gained independence from British rule.
Talks between India and Pakistan on that border issue began today in Islamabad as part of the composite peace dialogue.
Indian Petroleum Secretary MS Srinivasan says the pipeline -- which could pass through the marshy border region -- is vital to India's national interests:
"We consider that this project is necessary and important to us in order to meet our growing energy needs and our requirements," Srinivasan said. "And our national interest will determine the progress of the project."
Another unresolved issue is how much Islamabad would charge for the transit of Iranian gas deliveries to India. Officials from all three countries plan to meet in New Delhi in July to try to reach agreement on a gas pricing mechanism.