(Bloomberg) — Traffic through the vital Strait of Hormuz has been picking up in the past week, with the seven-day rolling average for transits on Friday reaching the highest since the war started.

More vessels are crossing, including those with no clear links to Iran or China, as nations negotiate with Tehran to get their ships through. Transits over the past day were led by liquefied petroleum gas carriers, including one headed to India and others with Iranian affiliations.

A total of 13 ships have crossed since Friday morning, with 10 exiting the Persian Gulf and three entering from the open seas, according to vessel-tracking data compiled by Bloomberg. Still, that’s a trickle compared with the numbers before the war began on Feb. 28. In normal times, about a fifth of the world’s oil and liquefied natural gas passes through the strait every day.

Iran has moved to tighten its control over the waterway, setting up a tolling system and directing most vessels to take a specific route close to its border. In the past day, all recorded transits went through that narrow northern passage, situated between the Iranian islands of Larak and Qeshm.

Recent crossings include a French container ship and a Japanese-owned LNG tanker, seemingly the first such transits since the war began. It’s not clear whether those journeys were a result of diplomatic outreach or negotiations by shipping companies and their intermediaries.

Tanker-tracking is hampered by electronic interference with ships’ signals, and some vessels disable their AIS transponders in high-risk waters, further reducing the timeliness and reliability of tracking data.

Outbound Transits

Five bulk carriers and one oil-product tanker joined the four LPG tankers in exiting the Persian Gulf since Friday morning. Three of the bulkers and the fuel tanker sailed on Saturday morning. Apart from the Indian LPG vessel, the others are linked to Chinese or Iranian interests.

With vessels going dark in high-risk waters, transit counts may initially appear lower and may be revised upward as delayed data becomes available.

Inbound Transits

Two LPG carriers and one fuel tanker with Iranian affiliations were among the inbound transits recorded since Friday morning.

NOTES:

Because vessels can move without transmitting their location until they’re well away from Hormuz, automated positioning signals were compiled over a large area covering the Gulf of Oman, the Arabian Sea and the Red Sea to detect those that may have departed or entered the Persian Gulf.

When potential transits are identified, signal histories are examined to determine whether the movement appears genuine or is the result of spoofing — where electronic interference can falsify the apparent position of a ship.