Speaking at the opening ceremony of the 31st International Islamic Unity Conference on Tuesday in Tehran, Dr Rouhani added: "Recklessness of some states of the region in cooperating with the Zionist Regime is the bitter part of the recent developments ".
"What made the days of unity of this year sweeter, was the victory of the armies in the region over terrorism and the uncovering of the conspiracies of powers and Zionism against the nations of the region," he continued.
Dr Rouhani said: "The people of Palestine, the people of the region, and the ulama, the elites and the youth will never forget the plights and animosity of Zionism and the occupation of the Palestinian land, and the freedom of the Holy Quds will always be a wish of the Muslim nations of the region."
The president referred to the plots of the Global Arrogance and Zionism in the region, saying: "It is clear that the major world powers, including the United States and the Zionism, have made terrorist groups for the people of the region to grapple with. We know this and they also have no way but to confess".
"What made the days of unity of this year sweeter, was the victory of the armies in the region over terrorism and the uncovering of the conspiracies of powers and Zionism against the nations of the region," he continued.
He added: "Everyone knows who created al-Qaeda and terrorists in the east of the region in Afghanistan and Pakistan, and we know who gave the terrorists money and weapons and provided them with technical and information assistance," saying that the snake they bred to bite others, attacked themselves as well.
He went on to say: "The most terrible act by terrorists was burning the opportunities for the development of Iraq, Syria and the region".
Stating that whenever opportunities for Iran's development were provided, they began a conspiracy, Dr Rouhani added: "Saddam's attack on nuclear slanders and threats and sanctions were conspiracies against Iran's development; they are now thinking about new plots".
"Syria and Iraq will be completely united and prevail over terrorism sooner or later, and the Yemeni people will make the aggressors regret," he added.
The President also said: "It has been for 40 years that the Iraqi people have been plagued by conflicts that powers have plotted".
He continued: "World powers must be accountable for killing the region's youth and destroying its historical and infrastructural monuments".
Shiites and Sunnis in the peninsula, Africa, and the region fought together against colonialism, said Rouhani, adding: "Shiites and Sunnis have learnt from the Qur'an how to be brothers and speak softly".
President Hassan Rouhani also said: "The wars will end, but the hatred that the Arrogance has created by supporting the bloodshed will remain for many years".
He continued saying: "The main task of the scholars of religions and elites is to heal the profound wounds that colonialism has created over the years".
Betraying other countries is compensable, but betraying Islam has put a heavy burden on us, he said, adding: "They have shown a completely different face of Islam; scholars, writers and the media must show the true face of Islam".
Stressing that unity and development are possible only through moderation, the President of the Islamic Republic of Iran also said: "We will not achieve Islamic unity and civilisation by violence and terror".
"The meaning of unity is not to destroy a branch and develop another; different branches of Islam must sit around a table," he went on to say.
We are one and the same when principles of religious and ethics are concerned, and we must stand together, said Rouhani adding: "God has commanded unity alongside monotheism and prophecy".
He continued: "Unity means to be united to liberate Islamic countries from the intruders. If the authorities of Islam were not beside the government, and ethnic groups were not beside branches, ISIS had dominated a great part of Iraq today".
Stating that "if the army, people, and the Resistance in Syria were not united, ISIS would not end there", he said: "Iran, from the east and Sistan and Baluchistan, to the west and Kurdistan; enjoys security thanks to the scholars and intellectuals working under the shadow of unity".
Stating that the Islamic unity must be moderate, Dr Rouhani said: "This is what Islam has commanded us. Even in jihad and conflict, God has ordered moderation".