German Chancellor Angela Merkel plans to visit Israel next month on a trip meant in part to signal solidarity following recent anti-Israel remarks by the president of Iran, the German government said Sunday. Merkel will travel to Israel in late January, a government spokeswoman said on the customary condition of anonymity. The visit will underline "Germany's unconditional defense of Israel's right to exist," she added, confirming a report by the weekly Der Spiegel that one of the trip's aims is to send a signal of opposition to recent comments by Iranian President Mahmoud Ahmadinejad. Ahmadinejad aggravated tensions last week by calling the Nazi Holocaust a "myth," two months after he called for Israel to be "wiped off the map." German Foreign Minister Frank-Walter Steinmeier wrote in an article for the Bild am Sonntag newspaper that the president's comments constituted a test for German-Iranian relations. He added that "Iran could become completely isolated internationally." "If Iran wants to be a respected partner of Europe, its president can neither deny historical truths nor threaten Israel," the minister wrote. "Only an Iran that shows responsibility and keeps to the international rules can be a respected member of the international community." Steinmeier renewed his warning that Ahmadinejad's outbursts will make talks between European negotiators and Tehran on Iran's nuclear program more difficult.