Al-Qaeda, Iran: Common interests, common foes
Despite ideological differences, Iran has become the prime haven of al-Qaeda's leaders.
It provided protection to al-Qaeda's senior leader Mohammed Salah al-Din Zaidan, codenamed 'Sword of Justice'.
In January, Washington revealed the existence of two al-Qaeda stations in Iran: inside Tehran and the city of Mashhad in north-eastern Iran, adjacent to the Afghan border.
The two stations facilitate the travel of ISIS elements to and from Afghanistan.
Former US Secretary of State Mike Pompeo and Director of the Bureau of Counterterrorism at the US State Department, Nathan A. Sales, confirmed that Iran allows al-Qaeda to move, transfer fighters and funds to neighbouring countries.
They referred to common interests between these organizations, on one hand, and Iran, on the other.
Retired general of the Iranian Revolutionary Guard, Saad Qasemi, acknowledged close relations with al-Qaeda previously.
We fought, he said, alongside al-Qaeda.
Director of think tank, Giddar Centre for Iranian Studies, Mohamed Abadi, said relations between Tehran, on one hand, and al-Qaeda, on the other, are ones of common interests, despite ideological disagreement between them.
"Al-Qaeda fights the Shiite doctrine according to its method," he told The Reference.
Relations between the two sides, he added, are based on the 'enemy of my enemy is also my enemy' rule.
"Iran is the enemy of the US," Abadi said. "Al-Qaeda is also the enemy of the US."
Abadi pointed to another reason for close relations between the two sides, namely the border linking Afghanistan with Iran.
Due to geographical proximity, he said, Tehran provided financial and logistical support to al-Qaeda during the Soviet invasion of the country.
"This was when both sides were against the Soviet Union," he said.
He noted that Iran uses al-Qaeda against the West, and also uses it as a bargaining chip when necessary.
In return, Abadi said, Iran provides al-Qaeda with financial and military support.
He added that despite that relation, al-Qaeda launches attacks on Shiites in Iraq from time to time.
According to Foreign Affairs magazine, Iran seeks to keep the leaders of al-Qaeda to ensure that the organization does not carry out attacks against it, especially since it has previously attacked Iran's arms in several areas, including the Lebanese Hezbollah and the Houthi group in Yemen.
The magazine points out that the presence of these leaders in Iran does not necessarily mean that Tehran provides material support for al-Qaeda's operations.
Political analyst Mohammed Hussein said it is in Iran's interest at the moment to support al-Qaeda more than before to protect its Houthi group in Yemen.
"What Tehran planned has already happened," Hussein told The Reference. "This contributed to the presence of strong relations between the Islamic Republic and al-Qaeda."