Egypt’s President Mohammed Morsi arrived in Tehran on Thursday in the first visit by an Egyptian leader to Iran in decades, using the occasion to call out the Syrian regime.

The Egyptian president is attending a summit of the Non-Aligned Movement in Iran, which the country is using as a means to bolster its international standing in the face of isolation over its nuclear program.

Iran’s state TV in a live broadcast showed Morsi being received by Iranian President Mahmoud Ahmadinejad at the summit conference hall in Tehran.

Morsi denounced former ally Syria over the bloody uprising there, calling the regime of President Bashar Assad “oppressive.”

“We should all express our full support to the struggle of those who are demanding freedom and justice in Syria and translate our sympathies to a clear political vision that supports peaceful transfer [of power] to a democratic system,” Morsi said in his opening statement.

Morsi slammed Syrian President Bashar Assad’s rule, saying that the world had a “moral duty” to stand with the Syrian people in their struggle “against an oppressive regime that has lost its legitimacy.”

He said having a democratic system in Syria “reflects the desire of the Syrian people for freedom, justice and equality and at the same time protects Syria from entering into a civil war or being divided by sectarian clashes.”

Iran’s Supreme Leader Ayatollah Ali Khamenei told the summit his country has never pursued nuclear weapons but it would not abandon its controversial nuclear program.

Khamenei, who has final say on all state matters in Iran, says the country considers the use of nuclear weapons to be “a big and unforgivable sin.”

Tehran has an ambitious agenda for the summit, including the launching of a peace effort including Egypt, Iran, and three other countries to help resolve the crisis in Syria.

The two countries remain divided over Syria’s crisis. Shiite Iran backs the Damascus regime, while there is widespread sympathy in Egypt for the rebels seeking to oust President Bashar Assad. Anti-regime fighters have dismissed any role for Iran in a plan they and some others say has little hope of succeeding.

Morsi’s visit was historic, but Egyptians officials have indicated it does not necessarily represent a thaw in relations between the two countries.

Tehran cut diplomatic relations in 1979 because of Egypt’s peace accord with Israel. Since the 1979 Islamic revolution, Iran has considered Israel as its arch foe.

Iran’s leadership welcomed the 2011 uprising in Egypt that ultimately brought Morsi, an Islamist, to the presidency.

Iran sees the summit as an opportunity to counter US claims that it has been isolated over its nuclear program. The West says Iran is trying to develop weapons while Tehran says the program is for peaceful purposes.

Morsi arrived in Iran after three days in China, where he made waves Wednesday after announcing his intention to restart Egypt’s nuclear power program, which was initiated by Gamal Abdel Nasser in the early 1960s under Soviet patronage.

Egypt, a signatory of the Nuclear Non-Proliferation Treaty, most recently signed an agreement with Russia in 2008 to further develop its nuclear power facilities.

Reportedly, Iran has offered to give Morsi a tour of its Bushehr nuclear reactor, located along the coast of the Persian Gulf.

Responding to a question on Israel Radio about a potential renewal of Egypt’s nuclear program, Israeli Defense Minister Ehud Barak said Israel was not worried by the development.

“Many countries have nuclear reactors for peaceful purposes,” he said. “The problem is when a country decides that under this shelter they will make the effort to obtain nuclear weapons, which is a very serious situation. But we have no indication that Egypt is going in that direction.”