President Hassan Rouhani blamed Israel and the U.S. Thursday for a suicide bomb attack that killed 27 members of the Revolutionary Guard in southeastern Iran.

The bomber drove a car laden with explosives Wednesday into a bus carrying members of the elite paramilitary force in Sistan and Baluchistan province, a mountainous region along the borders of Pakistan and Afghanistan.

A militant Sunni Muslim group called Jaish al-Adl (Army of Justice), who are seeking greater rights and better living conditions for the ethnic minority Baluchis, claimed the attack.

Tehran has in the past blamed its regional rival Saudi Arabia for supporting Sunni militants, but this time Iran’s leader pointed the finger straight at Washington and Tel Aviv:

“The crime will remain as a ‘dirty stain’ in the black record of the main supporters of terrorism in the White House, Tel Aviv and their regional agents,” Rouhani said, ahead of a trilateral meeting with Turkish President Recep Tayyip Erdogan and Russian President Vladimir Putin in Sochi.

Supreme Leader Ayatollah Ali Khamenei also weighed in, saying, “There is a link between this crime and some regional and international spying and intelligence agencies.”

Rouhani, Khamenei and the leader of the Revolutionary Guard all promised swift action to bring those responsible to justice.

The attack took place on the same day that officials from around the world gathered at a U.S.-sponsored conference in Warsaw billed as a discussion on peace in the Middle East.

However, the conference’s unofficial focus was firmly on Iran — a fact highlighted by Israeli Prime Minister Benjamin Netanyahu, who posted a tweet threatening war with the Iranian regime.

Donald Trump’s personal lawyer Rudy Giuliani stoked further anger by addressing an anti-Iran rally outside Warsaw’s main stadium, calling Iranian leaders “assassins, they are murderers and they should be out of power.”

Giuliani said he was in Warsaw representing an Iranian opposition group, the Mujahedeen-e-Khalq, or M.E.K, and not Trump. However, Tehran was quick to link the attack on the Revolutionary Guards to the meeting in the Polish capital.

“Is it no coincidence that Iran is hit by terror on the very day that #WarsawCircus begins?” Iran’s Foreign Minister Mohammad Javad Zarif wrote on Twitter. “Especially when cohorts of same terrorists cheer it from Warsaw streets & support it with bots?”