The US ambassador to Germany has resigned from his post and the state Department after two years in the job

Grenell confirmed his retreat late on Monday on his Instagram account without indicating his next post.

It has been widely speculated that he may join US President Donald Trump’s re-election campaign,

President Trump named Grenell ambassador to Germany in April 2018.

He has also long been finding things to pick at about the Nord Stream 2 project, which is designed to transport natural gas from Russia to Germany through the Baltic Sea.

Although German ministers have refrained from radical responses to Grenell, parliament members have often openly denounced his remarks, and some lawmakers even asked foreign ministry to declare him as “persona non grata” — an unwelcome or unacceptable person in diplomacy.

Grenell was tapped in February to become the acting director of national intelligence. The decision was criticized by Democrats who said he lacked necessary experience.

Last month, the Senate confirmed John Ratcliffe as director of national intelligence, succeeding Grenell, who remains Trump’s envoy to Kosovo and Serbia.

(With inputs from agency)