BERLIN (Reuters) - Germany welcomed U.S. Secretary of State Rex Tillerson s announcement that he was  probing  opportunities for dialogue with North Korea about its nuclear weapons program and called for Washington to take a similar step with Iran. German foreign minister Sigmar Gabriel also warned in a statement that going back on a nuclear deal with Iran signed by former U.S. President Barack Obama would risk undermining Washington s credibility in negotiating with North Korea. In 2015, Tehran agreed to restrict its nuclear program in return for the loosening of economic sanctions that had crippled its economy. But U.S. President Donald Trump has called the deal  an embarrassment  and Washington said last month it was weighing whether to pull out of it. Germany, one of the few Western countries with a permanent embassy in Pyongyang, has advocated peaceful approaches to de-escalating tensions on the Korean peninsula and criticized some of Trump s more bellicose rhetoric regarding the potential nuclear flashpoint.  This is exactly the right direction. North Korea would be well advised to take this offer of talks seriously.  Gabriel said on Sunday of Tillerson s announcement. He added:  I would like to see a similar offer for Iran. If the U.S. canceled its nuclear deal with Iran, that would undermine the credibility of its offer to North Korea.  