Manama- Defence Secretary Jim Mattis will stress the US commitment to Middle East security at the weekend, officials said, amid Western concern that any loosening of US ties to Riyadh after Jamal Khashoggi’s murder could allow Russia to fill the vacuum.

Mattis will give a speech at the annual Manama Dialogue security conference in Bahrain on Saturday on the United States’ policy in the Middle East which will be closely watched in capitals around the region.

Katie Wheelbarger, the principal deputy assistant secretary of defense for international security affairs, said that Mattis’ speech would emphasise that the United States was committed to help allies “re-instill stability in a chaotic region.” “So continue to look to the United states as your security partner of choice because you can rely on us and depend on us to be there long term,” Wheelbarger told reporters travelling with Mattis.

There is increasing concern that if Washington abandons the region, countries like Russia will fill the vacuum.

Nowhere will the speech be watched more closely then in Riyadh, after Saudi Arabia’s public prosecutor said the murder of journalist Jamal Khashoggi in the kingdom’s Istanbul consulate this month was premeditated.

After Saudi King Salman spoke to Russian President Vladimir Putin on Thursday about the killing, the Kremlin said Russia had no reason to doubt the statements of the king and crown prince that the royal family was not involved.