Croatia's defence ministry said that the country's 14 troops in Iraq have been moved to Kuwait amid soaring tensions after a United States airstrike killed Iran's top commander Qassem Soleimani in Baghdad last week.

The statement says any future steps also will be made in consultation with Nato allies.

A growing number of European countries are shifting troops out of Iraq.

Germany says it has moved 35 soldiers serving in Iraq to neighbouring Jordan and Kuwait. Slovakia says it has moved its seven service members from Iraq to an unspecified location.

Slovenia, however, says its six soldiers in Iraq are staying there. They are posted at the Erbil base in northern Iraq. The defence ministry says it is constantly monitoring the situation and will make further decisions based on future developments.

Meanwhile, the Japanese Foreign Ministry issued a warning to its citizens in the Middle East citing security concerns after Iran said it would retaliate against the US following Soleimani's killing.

The Japanese warning, dated Sunday, tells citizens to stay in a safe area, maintain communications channels and keep family and friends updated on whereabouts.

Earlier, British Foreign Secretary Dominic Raab travelled to Brussels for talks with European counterparts about the situation in the Middle East.

The talks are expected to assess the state of Iran's 2015 nuclear deal with world powers after Tehran announced on Sunday it is withdrawing from further commitments in the agreement.

Raab will have a bilateral meeting with the French foreign minister, Jean-Yves Le Drian, before meeting with German and Italian counterparts.