Qatari mediators spent more than 12 hours in Tehran on Friday seeking to revive direct negotiations between the United States and Iran, CNBC World Economy reported, citing an official familiar with the discussions. The effort aimed to secure an agreement that would avert a possible return to American-led attacks after the US midterm elections, as reports of shipping incidents in the Strait of Hormuz added to pressure on oil markets.

The official, who spoke anonymously, said the discussions involved Iranian officials. Axios, which first reported the meetings, said talks were due to continue in Doha on Saturday. However, Iranian Foreign Minister Abbas Araghchi said there were no plans for meetings with US officials. According to Al Jazeera, he confirmed that an Iranian delegation had travelled to Qatar to meet mediators but dismissed reports of a US meeting as speculation.

A preliminary US-Iran agreement signed on 17 June to stop the fighting collapsed weeks later. The conflict began on 28 February with US and Israeli strikes against Iranian targets. CNBC reported that the latest confirmed US strikes took place on 1 September. President Donald Trump has left open the possibility of further attacks after the 3 November elections and said on Tuesday that ending the war required an unequivocal commitment that Iran would never possess a nuclear weapon.

Tehran has said it is preparing to respond militarily to further US strikes. A statement on Supreme Leader Mojtaba Khamenei’s Telegram account on Saturday warned that responses to threats would be immediate and would have no geographical limits. Separately, Iranian media reported an alleged US attack on two fishing boats near Qeshm Island. That account was not independently confirmed, and US Central Command did not immediately answer CNBC’s request for comment.

The United Kingdom Maritime Trade Operations Centre said on Friday that an unidentified projectile had struck a crude tanker leaving the strait. Iran separately reported that four tankers had hit mines, while Yemen’s Houthis claimed missile attacks on Saudi Arabia. Oil prices rose more than 2% on Friday, reaching their highest settlements since late April, according to CNBC. The expiring December Brent contract gained $2.76, or 2.4%, to $117.64 a barrel; the more actively traded January contract rose $2.63 to $113.43.