BERLIN (Reuters) - Support for Chancellor Angela Merkel’s conservative bloc is up despite the Christmas market attack in Berlin that killed 12 people, and most Germans are not worried about terrorism, an opinion poll showed on Friday.

German Chancellor Angela Merkel walks before delivering a statement in Berlin, Germany, December 23, 2016. REUTERS/Hannibal Hanschke

Merkel’s conservative “Union” alliance of her Christian Democrats (CDU) and the Bavarian Christian Social Union (CSU) rose 2 percentage points from a month ago to 37 percent, the survey by pollster Infratest dimap for broadcaster ARD showed.

The poll of 1,505 voters was conducted from Jan. 2 to Jan. 4. The Berlin attack, in which a rejected asylum-seeker from Tunisia drove a truck into a Christmas market, took place on Dec. 19. He fled and was shot dead by Italian police in Milan four days later.

The centre-left Social Democrats (SPD), junior partner in Merkel’s ruling grand coalition, slipped 2 points to 20 percent. The anti-immigration Alternative for Germany (AfD) gained 2 points from a month ago to 15 percent, the poll showed.

Merkel’s government has proposed new security measures in response to the Berlin truck attack claimed by Islamic State, triggering fierce debate in an election year in which the chancellor, 62, is seeking a fourth term in office.

A separate Infratest dimap survey for ARD showed 73 percent of Germans felt safe despite the Berlin attack. AfD supporters were an exception - two thirds of them did not feel safe.

Refugee policy will be the biggest issue for voters in September’s federal election, the poll showed.

Merkel’s conservatives have been bleeding support to the AfD over her open-door policies that allowed into Germany about 1.1 million refugees from Syria, Iraq, Afghanistan and elsewhere since mid-2015.

The Bavarian CSU has long bristled at Merkel’s migrant stance and insisted on a limit of 200,000 refugees per year, which she rejects.

Seeking a compromise to end their row before they head into the election together, the CDU and CSU on Thursday floated the idea of a flexible target for how many asylum seekers Germany should accept each year.