Humza Yousaf was sworn in as Scotland’s new leader on Wednesday in a ceremony that blended formal tradition with his Pakistani heritage before he announces appointments to his cabinet that risk worsening the deep divisions in his governing party.

Yousaf, the first Muslim to lead a democratic western European nation, was dressed in a black shalwar kameez at Scotland’s highest court, the Court of Session in Edinburgh, as his family watched on.

The 37-year-old pledged an oath of allegiance to King Charles. He has previously said he wants to replace the monarchy with an elected head of state if he achieves his dream of ending Scotland’s three-centuries-long political union with England.

Yousaf narrowly won a leadership race on Monday after a bruising contest that followed the surprise resignation last month of Nicola Sturgeon, who had dominated Scottish politics for almost a decade.

The internal disagreements over the future of the pro-independence Scottish National Party and the country re-emerged after Yousaf’s main rival, Kate Forbes, quit the government.

Forbes turned down an offer to become the minister for rural affairs and islands, a step down from her previous role as finance minister, according to the BBC and Scottish newspapers.

Former health secretary Alex Neil, who backed Forbes, said the proposed post was “an insult and not a real effort to unite” the party.

Yousaf had been expected to offer his leadership rival, whom he only defeated by only about 2,000 votes, a more senior role.

During his leadership campaign, Yousaf had said he would depart from Sturgeon’s “inner circle” style of leadership in favour of a “big tent” approach.

Forbes, who had questioned Yousaf’s record in government during the leadership campaign, posted on Twitter a reminder of the closeness of the contest, while saying Yousaf had her “full support”.

Yousaf said on Tuesday that Shona Robison — a close friend of Sturgeon — will serve as his deputy first minister. More appointments to cabinet roles are expected on Wednesday afternoon.