OSLO (Reuters) - Iranian Foreign Minister Mohammad Javad Zarif said on Tuesday Saudi Arabia was supporting militants inside Iran, days after hardline Sunni group Islamic State claimed attacks in Tehran.

Iran's Foreign Minister Mohammad Javad Zarif smiles during the opening of the Oslo Forum at Losby Gods outside Oslo, Norway June 13, 2017. NTB Scanpix/Hakon Mosvold Larsen via REUTERS

Zarif also called on countries in the region to establish a regional forum to resolve conflicts.

Relations between the two neighbors are at their most tense in years. Last week Riyadh, along with other Arab governments, severed ties with Qatar, citing its support of Iran as one of the main reasons for the move.

Two days later, suicide bombings and shootings in Tehran killed 17 people. Iran repeated accusations that Saudi Arabia funds Islamist militants, including Islamic State. Riyadh has denied involvement in the attacks.

“We have intelligence that Saudi Arabia is actively engaged in promoting terrorist groups on the eastern side of Iran, in Baluchistan,” Zarif told a news conference held on the sidelines of a conference on peace mediation in Oslo.

Baluchistan province is home to a Sunni population who form a minority in majority Shi’ite Iran.

Iran and Saudi Arabia accuse each other of subverting regional security and support opposite sides in conflicts including those in Syria, Yemen and Iraq.

“On the Western side, the same type of activity is being undertaken, again abusing the diplomatic hospitality of our other neighbor,” he said, without elaborating.

Iran also accuses the United States for promoting Islamist militancy in the region.

Zarif also called on the establishment of a regional forum to resolve differences, made more necessary by the ongoing tensions between Qatar on the one hand and Saudi Arabia, Egypt, the United Arab Emirates and Bahrain on the other.

“It is absolutely imperative... to establish a permanent mechanism for consultation, conversation and conflict resolution in our region, using some variation of the Helsinki approach,” said the foreign minister, in reference to the 1975 Helsinki Accords.

“I think it worked at the height of the Cold War here in Europe, it should work (for the Middle East too).”

Asked about U.S. President Donald Trump’s descriptions of Iran, which he described in a recent tweet as a state sponsoring terrorism, Zarif referred to the fact that most of the September 11 attackers were Saudi nationals, rather than Iranians.

“President Trump is trying to change the nationality post-mortem of 15 of the 19 September 11 suicide bombers, or of every other suicide bomber that attacked U.S. soil or any Western country over the past 20 years,” he said.

“They did not come from Iran. None. Why is he trying to change history? We are not intimidated by these moves.”