BERLIN: The US has formally asked Germany to join France and Britain in a mission to secure the Strait of Hormuz and to combat Iranian aggression, the US Embassy in Berlin said on Tuesday.

At a time of heightened tension between the United States and Iran, Washington has proposed stepping up efforts to safeguard the Strait of Hormuz in the Gulf, through which about a fifth of the world's oil passes.

“We’ve formally asked Germany to join France and the UK to help secure the Straits of Hormuz and combat Iranian aggression. Members of the German government have been clear that freedom of navigation should be protected... Our question is, protected by whom,” said an Embassy spokeswoman.

The comments, initially reported by Germany's DPA news agency, were confirmed by an Embassy spokesman.

Ties between Iran and the United States have deteriorated since Washington pulled out of an international nuclear deal with Iran last year and reimposed sanctions on Tehran. Recent attacks on oil tankers in the Strait of Hormuz have further soured relations.

There is considerable opposition among Germany's Social Democrats (SPD), junior partners in conservative Chancellor Angela Merkel's ruling coalition, to getting involved in a US-led mission.

“The German government has already rejected participation in the US military mission, Operation Sentinel, to protect shipping in the Strait of Hormuz,” said Nils Schmid, a foreign affairs spokesman for the SPD parliamentary party.

“It should stay like that. Otherwise, there is a risk of being pulled into a war against Iran on the side of the United States,” he added in an interview with the Stuttgarter Zeitung.