By Jonathan Saul

LONDON (Reuters) -Iran and Israel accused each other of endangering commercial activity in sea lanes around the Gulf and the Red Sea at the UN's shipping agency on Wednesday, as their military conflict escalated.

Iran's delegation told a session of the International Maritime Organization's security committee that Israel had in recent days extended its "unlawful attacks" to include petrochemical and gas infrastructure in Asalouyeh along Iran's Gulf coast.

"These actions directly endanger international maritime security and the global energy supply chain," Iran said in a statement to IMO delegates, which was livestreamed.

"If the international community fails to take urgent and concrete measures to halt this unlawful aggression, the risk of escalation at sea becomes imminent."

Iran has previously threatened to close the Strait of Hormuz to traffic in retaliation for Western pressure. Any closure of the strait could restrict trade and affect global oil prices.

Commercial ships are being advised by maritime agencies to avoid Iran's waters around Hormuz, shipping sources said on Wednesday.

Former Iranian Economy Minister Ehsan Khandouzi has said that tankers and liquified natural gas cargoes should only transit the Strait of Hormuz with Iranian permission.

Iranian Supreme Leader Ayatollah Ali Khamenei rejected Donald Trump's demand for unconditional surrender on Wednesday, and the U.S. president said his patience had run out, though he gave no clue as to what his next step would be.

Israel's mission told delegates the IMO's foundational principle of global maritime navigation safety was being "openly and aggressively threatened" by Iran, partly through support of Yemen's Houthi militia, whose attacks have severely disrupted shipping through the Suez Canal and Red Sea in recent years.

"Iran has turned our whole region and the Red Sea specifically into a war zone. Through its political, financial and military backing of the Houthi rebels, Iran has enabled a campaign of maritime terrorism against civilian vessels," Israel said.

"It seeks to weaponize the world's busiest sea lanes, hold international shipping hostage, and impose its will through violence."

The London-based IMO is responsible for regulating the safety and security of international shipping and preventing pollution and comprises 176 member state countries.

The statements from Israel and Iran on Wednesday were noted by the Maritime Safety Committee, an IMO spokesperson said.

The agency has faced growing pressures that it was becoming politicised.

In 2023 Russia said the IMO was departing from its technical role because of "external pressure", which was impacting the fair treatment of all member countries.

Iran's offer to host a maritime event in 2023 was rejected after a proposal led by the United States to rescind the bid was approved in a vote.

(Reporting by Jonathan SaulEditing by Alexandra Hudson)