LONDON, May 4 (Xinhua) -- The maritime security threat level in the Strait of Hormuz remains "critical" due to ongoing regional military operations, the United Kingdom Maritime Trade Operations (UKMTO) said in an advisory on Monday.

The advisory came after U.S. President Donald Trump said on Sunday that the United States would begin a transit facilitation operation on Monday to "guide" stranded ships through the waterway.

The agency confirmed that the United States has established an enhanced security area south of the Traffic Separation Scheme (TSS) in the Strait of Hormuz to support vessel transits.

However, it warned that navigation within or near the TSS should be considered "extremely hazardous" due to the presence of mines that have not been fully surveyed and mitigated.

The Strait of Hormuz traditionally operates under a TSS, forming two separated lanes located in Iranian and Omani waters, with the southern lane running closer to Oman. Since the outbreak of the conflict, traffic through the TSS has declined markedly.

Iran has since set up an alternative route near its territorial waters and requires vessels to coordinate with its authorities prior to transit.

Also on Sunday, the UKMTO reported two maritime security incidents in waters near the Strait of Hormuz.

In one case, the master of a bulk carrier reported being approached and attacked by multiple small craft approximately 11 nautical miles (20 km) west of Sirik, Iran. In the other, a tanker was struck by unidentified projectiles about 78 nautical miles (144 km) north of Fujairah in the United Arab Emirates.

Analysts said the tankers involved may not have activated their automatic identification systems and were likely attempting to transit the strait without prior coordination. ■