TEHRAN, Iran — The UN special envoy for Syria, Staffan de Mistura, has stated that the breakdown in relations between Iran and Saudi Arabia is not affecting his efforts to advance the work of the International Syria Support Group (ISSG). However, there are reasons to believe that Riyadh’s cutting of diplomatic and commercial ties with Tehran will have a negative impact on the ISSG’s ongoing efforts to resolve the Syrian crisis.

United Nations Security Council Resolution 2254, which calls for a cease-fire and a transitional government in Syria, was passed after serious efforts and consultations on behalf of the United States and its European partners to accommodate Saudi Arabia and Iran enough to sit at the negotiating table. Yet, with the recent negative developments regarding relations between Tehran and Riyadh, it’s unclear how the two countries will pursue negotiations within the framework of the ISSG.

Indeed, concerns over the potential negative impact of the deterioration in Iran-Saudi relations on finding a solution to the Syrian crisis have led the West to uncharacteristically perform the difficult balancing act of accommodating both Tehran and Riyadh in order to continue their presence at the sessions of the ISSG. In this vein, White House spokesman Josh Earnest has criticized Saudi Arabia over the execution of Shiite cleric Sheikh Nimr al-Nimr, while chiding Iran for the subsequent attacks on Saudi diplomatic facilities in Iran. EU foreign policy chief Federica Mogherini has taken the step of speaking by phone with the foreign ministers of Iran and Saudi Arabia, urging the two sides to calm tensions. In a statement, Mogherini also denounced the Saudis for the execution of Nimr. Separately, German Foreign Minister Frank-Walter Steinmeier has condemned the execution and ensuing attacks on Saudi diplomatic compounds, stressing the need for Iran and Saudi Arabia to ease their tensions. Moreover, British Prime Minister David Cameron canceled his planned visit to Saudi Arabia, while Canada has issued a statement condemning only the execution of Nimr.

The next session of the ISSG will involve representatives of the Syrian government and the opposition. While apparently still slated to be held in Switzerland on Jan. 25, it is certain that there will be many challenges at the negotiating table — and that the various parties’ positions will be far apart. Although the fate of Syrian President Bashar al-Assad is neither discussed in UN Security Council Resolution 2254 nor in the ongoing political dialogue, it is not yet clear what the different parties’ stances on this matter will be. Moreover, the classification of nonterrorist opposition groups allowed to have a seat at the table — a very important issue in the peace talks — has not yet been finalized. The list of acceptable opposition groups has to be approved by a committee, which includes Iran. If the list is not finalized in the coming days and weeks, it is clear that the ongoing diplomatic efforts must be considered a failure and the Jan. 25 ISSG session thus unlikely to yield important results.