Iran’s Supreme Leader has again cautioned people not to “break the rules” in the May 19 Presidential election, his latest implicit reference to the mass protests after the disputed 2009 vote.

Ayatollah Khamenei told a graduation ceremony at the Revolutionary Guards’ Imam Hossein University on Wednesday:

If the people participate [in an] orderly [way] in the election… it will bring about the glory of the Islamic Republic. But if they break the rules or cause misconduct, if they please the enemies with their words, the elections will end to our detriment.

As usual, Khamenei invoked the Western “enemy”, saying that it was seeking a change in Iran’s behavior — “no different from changing” the Iran’s system — through intervention in the election and an attempt to “make the economy stagnant and lagging…so that the people will lose hope in the Islamic Republic over economic problems”.

The Supreme Leader has repeatedly warned against dissent similar to that in 2009, when more than a million people marched after President Mahmoud Ahmadinejad was declared the victor over leading challenger Mir Hossein Mousavi. The regime eventually put down the protests through repression, widespread detentions, and the killing of scores of people.

In 2013, Khamenei accepted the surprise first-round victory of centrist President Hassan Rouhani, but in this campaign he has implicitly challenged Rouhani and his policy linking economic recovery to a foreign policy of engagement of other countries.

The Supreme Leader did not aim at Rouhani on Wednesday, but gave his firm support to the Revolutionary Guards after the President publicly criticized the elite military force in last week’s second Presidential debate.

Khamenei said enemies “rage” against the IRGC because they “have always been against the factors that” strengthen Iran. He added that “propaganda and media hype” frequently target Iran’s ballistic missile testing program because “military might” strengthens Iran.

Rouhani raised the political stakes in the debate by criticizing the missile tests for jeopardizing implementation of the July 2015 nuclear deal. He said that slogans on the missiles brought further condemnation of Iran, hindering the economic engagement necessary for recovery after years of US and European sanctions.

The Guards, who oversee the tests, have reportedly put inscriptions such as “Death to Israel”on the missiles.