Saudi Arabia promised on Thursday not to flood the oil market with extra barrels even as OPEC failed to agree on output policy, with Iran insisting on the right to raise production steeply. Tensions between the Kingdom and the Islamic Republic have been the highlights of several previous OPEC meetings, including in December 2015 when the group failed to agree on a formal output target for the first time in years. Tensions, however, were less acute on Thursday as Saudi Arabia's Minister of Energy, Industry and Mineral Resources Khalid Al-Falih, showed Riyadh wanted to be more conciliatory and his Iranian peer Bijan Zanganeh kept his criticism of Riyadh to an unusual minimum. In a rare compromise, OPEC also decided unanimously to appoint Nigeria's Mohammed Barkindo as its new secretary-general after years of friction over the issue. Saudi Arabia and its Gulf allies had tried to propose OPEC set a new collective ceiling in an attempt to repair the group's waning importance. But Thursday's meeting ended with no new policy or ceiling amid resistance from Iran. Despite the setback, Saudi Arabia moved to soothe market fears that failure to reach any deal would prompt OPEC's largest producer to raise production further. "We will be very gentle in our approach and make sure we don't shock the market in any way," Falih told reporters. "There is no reason to expect that Saudi Arabia is going to go on a flooding campaign," Falih said when asked whether Saudi Arabia could accelerate production. Zanganeh said Tehran would not support any new collective output ceiling and wanted the debate to focus on individual-country production quotas, effectively abandoned by OPEC years ago. "Without country quotas, OPEC cannot control anything," Zanganeh told reporters. He insisted Tehran deserved a quota — based on historic output levels — of 14.5 percent of OPEC's overall production. Zanganeh made a few conciliatory remarks, saying he was happy with the meeting and received no signals from other producers that they planned to increase output. Falih was the first OPEC minister to arrive in Vienna this week. "There could be shorter-term situations in which, in our view, OPEC might intervene and yet other situations — such as long-term growth of marginal barrels — in which case it should not," Falih told Argus Media ahead of the meeting.