The previously unannounced visit came as Tajikistan faces economic pressure from its neighbor Uzbekistan -- including cuts to badly needed electricity and natural gas supplies and the closure of road and railway connections between the two countries that Tajikistan needs as transit routes to Kazakhstan and world markets.
Analysts say the Aga Khan's visit is aimed at showing that Rahmon is not politically and economically isolated in his Central Asian former Soviet republic.
On April 4, Tajikistan's embassy in Moscow accused Uzbekistan of imposing a blockade in order "to make Dushanbe adopt decisions profitable for Tashkent."
But Uzbekistan has rejected those accusations.
Uzbekistan's Prime Minister Shavkat Mirziyaev said on April 4 that energy and transport links to Tajikistan have been cut due to "technical reasons."
Tajik officials have warned that a prolonged cutoff of energy supplies from Uzbekistan and cross-border transport could lead to a humanitarian disaster.
Electricity already is being rationed in Tajikistan because of shortages.
Investment In Several Areas
The Aga Khan, who runs a development network bearing his name, said his talks with Tajikistan's president on April 4 focused on difficult living conditions for many residents of the country after a long, harsh winter:
"With regard to the discussions with His Excellency the President we reviewed the situation in the region," he said. "And we spent some time looking at the questions concerning national infrastructure in Tajikistan -- because like many countries which are an integral part of a regional process, the way in which each country functions is very important indeed."
The Aga Khan told reporters after his talks with Rahmon that he will continue to invest in water, road, energy, and communications projects in Tajikistan. His network has already financed five key bridges in the country and a five-star hotel in Dushanbe as well as agriculture and education projects.
He indicated that his network has "an ongoing development program for Tajikistan" that would also cover other spheres of activity such as culture, health care, and economic development.
"We have a number of areas where we will continue to commit resources to the future of Tajikistan," he said.
With thousands of people who follow the Ismaili faith living in Tajikistan's eastern Badakhshan region, the Aga Khan also announced after his talks with Rahmon that an Ismaili center has been officially registered in Dushanbe under Tajikistan's law on religion.