Investigators say many British and American weapons have found their way into pro-Saudi and Yemeni groups in Yemen and splinter groups have links with al Qaeda and the Islamic state.

The Saudi newspaper The Guardian reported that Saudi Arabia and the UAE, in clear violation of trade agreements, have caused the arrival of some sophisticated weapons purchased from European and American companies, such as armored vehicles, rocket pads, improvised explosive devices and sophisticated guns to local militias.

The Guardian reported that a report prepared by journalist Mohamed Aboul Gheit and Arab journalists for the investigative journalism was broadcast in Arabic in a documentary film entitled "The Last Beneficiary".

According to the authors of the report, detailed information resulted from the analysis of thousands of media messages, the content of social media and closed Internet groups, as well as intensive research to verify weapons sources.

The documentary accuses the Saudi alliance in the war in Yemen, arms suppliers and governments of continuing violation of the laws of the "last beneficiary" certificate since the beginning of the conflict in 2015.

The purpose of these certificates is to assure the arms sellers or those issuing the sale permits that they will be used by the buyer only and will not be sold or passed on to the other beneficiary even if an ally.

The UN Security Council has issued a warning about the softening of accountability by the Saudi-UAE alliance in Yemen, and expressed concern that weapons have found their way to the black market.

Germany was the first European country to formally raise the issue of arms leaks with Saudi Arabia after a video showed that the Houthis had obtained G-3 rifles after being dropped from the air in their areas.

The paper pointed to the leakage of many of these German rifles to al-Qaeda in the city of Taiz in southwestern Yemen.

It also said that US "Oshkosh" anti-landmines, which bought Saudi Arabia and the United Arab Emirates (2600) and other improvised explosive devices (IEDs) and weapons, had reached Abu al-Abbas's hands in Taiz, Houthis, southern separatists and other groups.