At least ten vessels have been attacked in or near the Strait of Hormuz since Sunday, a high since war broke out between the United States, Israel and Iran, security data showed Wednesday.
Four vessels were struck on Tuesday and six on Sunday -- the highest number of attacks in a single day since the start of the conflict -- according to data from security firm Vanguard, the International Maritime Organization (IMO) and the British maritime agency UKMTO.
Two seafarers have been reported missing and a container ship reportedly sank as a result of recent attacks, according to the maritime sources.
Merchant vessels transiting the vital passage were first targeted by Iran in March in retaliation for US-Israeli strikes on its territory, and Tehran has continued to strike vessels passing through the strait via routes it has not approved.
The attacks have disrupted shipping through the strait, which is normally one of the busiest routes for exporting oil and other commodities from Gulf countries.
Twenty-three attacks have been recorded since the start of October, almost double the average monthly number of incidents since the start of the war.
The United States said on Saturday that it had struck a cargo vessel as part of its embargo on Iranian ports, but the incident was not listed by the IMO.
The recent uptick in energy exports, which almost returned to pre-war levels at the start of October but have since fallen back, may be behind the latest increase in attacks, according to Vanguard analyst Barun Gupta.
"Gulf oil flows have been recovering, with traffic through Hormuz recently returning to around 80 percent of pre-war levels despite the conflict.
"Increasing the tempo of attacks therefore gives Tehran a way of demonstrating that it can still disrupt that recovery and impose costs on commercial shipping and global energy markets," Gupta told AFP on Wednesday.
He said Trump's promise last week not to launch further attacks on Iran before the midterm elections in the US could also be a factor, giving Tehran "a perceived window to increase pressure with a lower immediate risk of US military escalation".
Some 24 seafarers have died as a result of incidents in the area near the Strait of Hormuz since the start of the conflict, according to the IMO.