German Chancellor Angela Merkel awaits the arrival of the new European Parliament President Antonio Tajani at the Chancellery in Berlin, Germany, February 24, 2017. REUTERS/Hannibal Hanschke

BERLIN (Reuters) - Germany’s Social Democrats (SPD) moved back ahead of Chancellor Angela Merkel’s conservatives in a poll by the INSA institute for Bild newspaper on Wednesday, marking the third time in the last three weeks the lead has changed hands in the INSA poll.

The INSA poll, which is more volatile than other leading polls, showed the SPD rising 2 percentage points in the last week to 32 percent, while the Christian Democrats and Christian Social Union (CSU) fell 1 point to 30.5 percent.

Three weeks ago, INSA had the SPD ahead of the CDU/CSU by 31-30.

Chancellor Angela Merkel is seeking a fourth term in the election on Sept. 24. Other polls show the two main parties running neck-and-neck.

In the INSA poll, the Greens were steady at 6.5 percent, the hard-left Linke fell 1.5 points to 8 percent, and the Free Democrats (FDP) gained 1.5 points to 7 percent. The anti-immigrant Alternative for Germany (AfD), which has no coalition allies, was unchanged, at 11 percent.