Story highlights Angela Merkel says, "The coming election will be difficult"

Chancellor notes pressure as a result of refugee crisis, Brexit vote

(CNN) One of the world's most powerful leaders has announced her decision to run for office again.

German Chancellor Angela Merkel put an end to months of speculation about her political future by saying she would seek a fourth term in next year's federal elections.

"I pondered a lot about it," Merkel told reporters at a news conference in Berlin. "The decision for a fourth term after 11 years is anything ... (but) trivial, not for the country and not for the party, and I say it consciously also for me personally."

Merkel, 62, said she expects the fall 2017 campaign to be her toughest to date.

"The coming election will be difficult," Merkel said. "We will probably be criticized from everywhere, from the right-wing parties and also because of the polarization of our society, also from the left party."