Scottish Justice Secretary Humza Yousaf encountered racist graffiti as he campaigned for re-election on Sunday.
The Scottish-Pakistani politician was unveiling the ruling Scottish National Party's minorities manifesto at a cafe in Glasgow that features a mural of Scottish footballer Andrew Watson.
The footballer, who played three times for Scotland in 1881 and 1882, is widely considered to be the first black player to feature at international level.
The mural was daubed with racist slurs criticising the Black Lives Matter movement.
Mr Yousaf, who is Scotland’s first Muslim cabinet minister, said the vandalism was disgraceful.
“It’s shameful that in this day and age in Scotland, in a really multicultural part of the city here in Glasgow’s south side, that the mural there to contribute to the first ever black football player who had played at international level has been defaced in such a way with racial slurs,” he said at the site of the mural.
He pledged all Scottish schoolchildren would learn about the country’s colonial past through an updated national curriculum if the SNP was re-elected on May 6.
“It’s easier for us all to unite and say, ‘I oppose racism’, but do we do enough to understand our own history when it comes to racism and structural barriers, and Scotland’s role in the slave trade?” he said.
“Walk anywhere in Glasgow and you see remnants of our historical slave trade and we can’t just sweep that under the carpet.”
The May elections are seen as crucial to Scotland’s independence movement.
Former SNP leader Alex Salmond is fielding candidates across Scotland in a major challenge to his successor, First Minister Nicola Sturgeon.
There are fears the newly formed Alba Party could split the independence vote, handing a major boost to UK Prime Minister Boris Johnson and his bid to prevent another referendum on the issue.
Mr Yousaf said the election campaign was particularly tough during Ramadan.
“I won’t lie – it’s quite tiring because you’ve got to get up at about 3.15 in the morning, drink a lot of water, try and eat as best as you can at that time,” he said.
“You just get on with it, it’s something that I choose to do, and if nothing else it will help me shift a little bit of lockdown weight, frankly, that I’ve put on over the last year.”