The Catholic Church does not have the power to bless same-sex unions, the Vatican office responsible for doctrine has said.

It is "impossible" for God to "bless sin", the Congregation for the Doctrine of the Faith (CDF) said on Monday.

But the CDF did note the "positive elements" in same-sex relationships.

In October, Pope Francis said in a documentary that he thought same-sex couples should be allowed to have "civil unions".

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In the Catholic Church, a blessing is given by a priest or other minister in the name of the Church.

In 2013 Pope Francis famously broke with doctrinal tradition, saying "Who am I to judge gay people?"
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image captionIn 2013 Pope Francis famously broke with doctrinal tradition, saying: "Who am I to judge gay people?"
On Monday, Pope Francis approved the response by the CDF, saying it was "not intended to be a form of unjust discrimination, but rather a reminder of the truth of the liturgical rite".

Some parishes in recent months, including in Germany and the US, have started giving blessings to people in same-sex relationships as a way to welcome gay Catholics to the church, Reuters news agency reported.

The CDF's response was in answer to the question posed to it: "Does the Church have the power to give the blessing to unions of persons of the same sex?". It replied: "Negative".

The CDF noted that marriage between a man and a woman is sacrament and therefore blessings cannot be extended to same-sex couples.

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"For this reason, it is not licit to impart a blessing on relationships, or partnerships, even stable, that involve sexual activity outside of marriage (i.e., outside the indissoluble union of a man and a woman open in itself to the transmission of life), as is the case of the unions between persons of the same sex," it said.

In 2013, Pope Francis famously said: "Who am I to judge gay people?"

Last year the pontiff said in a documentary by Evgeny Afineevsky that "homosexual people have a right to be in a family... they are children of God and have a right to a family. Nobody should be thrown out or made miserable over it".

The Vatican later attempted to clarify the comments saying they were taken out of context and did not indicate support for same-sex marriage.