Germany's interior minister on Monday denied reports that he was planning on stepping down as the nation's top security official but said he will relinquish his post as leader of the sister party to that of Chancellor Angela Merkel.

Horst Seehofer told reporters at an event in the eastern city of Bautzen that rumors he was resigning as interior minister were incorrect.

"I am the federal interior minister and I continue to serve in that office," the 69-year-old said.

Seehofer has clashed frequently with Merkel, primarily over her policies on migration. The friction between the two threatened to bring down the chancellor's coalition government earlier this year over his insistence that some categories of asylum-seekers should be turned away at the country's borders.

More recently, Seehofer's backing of domestic intelligence chief Hans-Georg Maassen over comments he made downplaying the extent of violence in anti-migrant protests in the eastern city of Chemnitz put him at odds again with Merkel as well as with other cabinet ministers.

Merkel's junior coalition partner Social Democrats had demanded Maassen's removal from the BfV spy agency in September after the comments.

Maassen was removed, and on Monday the ministry confirmed it was replacing him with longtime civil servant Thomas Haldenwang.

Despite staying on as interior minister, Seehofer confirmed that he had decided to step down from the Christian Social Union, which operates only in Bavaria as the partner of Merkel's Christian Democratic Union.

"I am taking this decision to make 2019 a year of renewal for the CSU," he said.

"Change is a part of life," he said, adding he'd announce specifics on timing later in the week.

Seehofer stepped down as Bavarian governor earlier this year in favor of a younger rival, Markus Soeder, but clung to the post of CSU leader until the party's dismal result in September's regional elections increased the pressure for him to leave.

His resignation comes after Merkel announced that her fourth term as chancellor would be her last and she would step down as leader of the Christian Democrats (CDU), the CSU's sister party on the national level.

Under Seehofer, the CSU, Merkel's Bavarian allies, suffered their worst results since 1950 in an election last month in the southern state after his anti-immigration campaign backfired.

Poor results for the CSU in Bavaria and Merkel's own CDU in the western state of Hesse have forced the long-serving chancellor to step down as party leader and announce her intention to retire from politics at the end of her term in 2021.

Meanwhile, Seehofer said his decision was not motivated by his party's losses in Bavarian state elections in October. Seehofer, who has held three different cabinet portfolios, has been a long-standing thorn in Merkel's side when it comes to refugees and migration.

He twice brought the government to the verge of collapse last year, including by threatening in the summer to prevent migrants from entering Germany via Austria.

Two months after Merkel heralded her open-border policy for the mass influx of refugees with her "We can do it" speech in August 2015, Seehofer threatened to take her to constitutional court. He repeatedly called for an upper limit on the number of refugees, characterized her unwavering stance on migration as a "reign of injustice" and once criticized Merkel while standing next to her on stage.

The former premier of Bavaria brought Merkel's coalition to the brink of collapse earlier this year by insisting on turning away asylum seekers at Germany's southern border. The government was deadlocked for weeks.

Seehofer also cozied up to Merkel's critics abroad, most notably Hungary's anti-immigrant prime minister, Viktor Orban, whose re-election he welcomed "in the name of the CSU," and the right-wing government of Austria, which shares a border with Bavaria, his party's home state.

More recently, Seehofer's backing of domestic intelligence chief Hans-Georg Maassen over comments he made downplaying the extent of violence in anti-migrant protests in the eastern city of Chemnitz put him at odds again with Merkel as well as with other cabinet ministers.

Merkel's junior coalition partner Social Democrats had demanded Maassen's removal from the BfV intelligence organization in September after the comments. Maassen was removed, and on Monday the Germany interior ministry confirmed it was replacing him with longtime civil servant Thomas Haldenwang.