"The Islamic Republic of Iran is ready and will spare no effort to help establish sustainable peace and fight terrorism in Afghanistan," Rouhani said in a meeting with Afghan President Ashraf Ghani on the sidelines of a summit of the Shanghai Cooperation Organization (SCO) in the Chinese port city of Qingdao on Saturday.
He added that Iran and Afghanistan have a common culture and trade interests and said, "Iran is determined to expand relations with [its] neighbors, particularly Afghanistan, and run a joint venture in various development projects such as transport infrastructure."
He stressed the importance of connecting regional countries, including Central Asian states, to the Persian Gulf, for the development of the entire region, Presstv reported.
The Iranian president also welcomed an Afghan government proposal to announce a ceasefire with the Taliban and expressed hope that intra-Afghan talks would lead to the promotion of stability in Afghanistan.
The Taliban announced in a statement on Saturday that it had agreed to a three-day ceasefire with Afghan security forces for Eid al-Fitr Muslim holidays in the middle of June, following a truce deal already proposed by President Ghani.
The ceasefire, the first offer of its kind, will begin either on Friday or Saturday, as Eid al-Fitr, which marks the end of the Muslim fasting month of Ramadan, falls on one of these days.
Elsewhere in his remarks, the Iranian president also called for cooperation between Iran and Afghanistan as well as other states in the region in the fight against the production and smuggling of illicit drugs, which he said constituted a problem for the entire region.
Enhanced cooperation with Iran serves Afghan interests: Ghani
The Afghan president, for his part, said development of cooperation with Iran would serve his country's national interests.
Ghani expressed hope that Iran would help Afghanistan restore security and said Kabul is ready to boost all-out cooperation with Tehran in the campaign against narcotics smuggling.
Iran, Belarus must use potential to strengthen ties: Rouhani
In a meeting with his Belarusian counterpart Alexander Lukashenko, the Iranian president said the two countries must make use of their utmost capacities to strengthen relations in all fields.
"Tehran is ready to expand and strengthen economic and share trade ties, particularly in the fields of science and modern technology, with the friendly country of Belarus," Rouhani added.
He emphasized that Iran is the best route for connecting the Central Asian and Caucasus countries as well as Southeastern European states to the Persian Gulf.
The Belarusian president, for his part, said his country is keen on promoting all-out relations with Iran as a key strategic partner.