Iran's President Hassan Rouhani has rejected the resignation of Foreign Minister Mohammad Javad Zarif, according to the country's semi-official Fars news agency, after Zarif announced he's stepped down via his official Instagram account late Monday. "The presidential office said the resignation had not been accepted," a foreign ministry spokesman said. According to Iranian law the president must formally accept the resignation before it takes effect.

Zarif wrote on Instagram as part of the shock announcement, "I sincerely apologize for the incapacity to continue serving and all the shortcomings during the service," and added the words, "Be happy and upbeat." Zarif was notably absent during official meetings related to Syrian President Bashar al-Assad's rare visit to Iran on Monday. It was the first time since the war began in Syria that Assad traveled to Iran.

Iranian President Hassan Rouhani, left, and FM Foreign Minister Mohammad Javad Zarif. File photo via IRNA

Though Ayatollah Khamenie, IRGC Quds force General Suleimani, and President Rouhani all met with and were photographed with Assad as part of the "working visit," Zarif — considered the father of the nuclear deal (a deal the hardliners have always said is a trap) — was nowhere to be seen, fueling speculation as to why such an important figure would be missing to receive the close foreign ally. It was soon after news of Assad's visit broke in international media that Zarif announced his resignation.

The foreign ministry's Tuesday statement further said that speculation about the reasons for Zarif's resignation beyond what was written on his Instagram page is incorrect, according to state media.

Much of that speculation centers around the possibility that Zarif took the drastic action in response to hardliners, represented in the military and especially the IRGC, who may be wielding undo influence over decision-making at the expense of the foreign ministry's authorized role.

The IRGC's Qasem Soleimani, for example, appeared alongside Assad during Monday's events as Zarif was absent. Soleimani is considered the key mover behind Iran's militarily propping up the Syrian government throughout the war.

Soleimani had made recent appearances on the Syrian battlefield, even at times appearing at frontline positions, where his presence has infuriated Sunni-led insurgents who oppose what they view as Shi’ite Iranian expansion in the region, as well as Israel, which fears Iranian expansion. Ayatollah Khamenei said during formal remarks greeting Assad on Monday that the Syrian-Iranian military alliance had dealt “a harsh blow” to US plans in the region, which involved empowering Gulf-aligned Sunni forces seeking to topple the Syrian state, and thus remove a key ally of both Tehran and Hezbollah.

Spokesman: President Hassan Rouhani Has Not Accepted Foreign Minister Javad Zarif’s Resignation pic.twitter.com/97Sz3jAeg5 — Fars News Agency (@EnglishFars) February 26, 2019

The empowering of IRGC commanders in the context of the Syrian war, and the simultaneous failure of the 2015 nuclear (JCPOA), overseen on the Iranian side by FM Zarif, may have brought internal tensions to a head Monday, represented in Zarif's sudden resignation. Tensions between the moderate camp (represented in Zarif) and the hardliners, which have the support of Khamenei, have long been boiling beneath the surface.

Writing of these tensions, Al Monitor's Iran Pulse Editor Mohammad Ali Shabani wrote in the wake of Zarif's resignation, via CNN: "Clearly there is dissatisfaction on Zarif's part with the way things are going in terms of the authority he and his ministry are experiencing." He added, "It's not something that happened overnight. It's been going on since day one."

Currently, it appears Rouhani is reaching out to Zarif. The president said in a speech on Tuesday that Syria's Assad had conveyed a personal thank you message to Zarif for his role as foreign minister, saying Iran's "great success" in standing up to US sanctions was in part due to the foreign ministry's efforts.

"He's been at the frontline of the battle against America," Rouhani said of his top diplomat in the speech.

"In the region we pulled off a great success and this great thing — this came on the back of efforts by all our forces. Part of that was on the shoulder of the foreign ministry, part of that was on the shoulder of the economy," said Rouhani.

Interestingly the text announcing the Iranian presidency's denial of Zarif's resignation was also published on Instagram, via Rouhani's official account accompanied by an image showing Rouhani and Zarif together and smiling. Additionally it included the hashtags "#Zarif_is_not_alone" and "#Zarif_is_staying" in Farsi.