From the BBC:

Danish MPs have cancelled a trip to Iran after Tehran demanded they apologise for the republication of cartoons deemed offensive to Islam.

Two days before the scheduled trip, Tehran demanded the MPs condemn the cartoon on their arrival in Iran. ...

A condemnation and apology would help convince the Iranian people that Denmark's authorities had distanced themselves from the action, Iran's parliament said in a letter to Danish MPs. 

"We are not the ones to apologise," said Villy Soevndal, the leader of Denmark's Socialist People's Party.

"If anyone needs to apologise for freedom of speech, human rights, imprisonments, executions and lack of democracy, it is the Iranians."