United Nations Secretary General Ban Ki-moon will attend a summit in Tehran despite Canada's best efforts to dissuade him from doing so, CBC News has learned.

Foreign Affairs Minister John Baird wrote to the UN chief last Thursday urging him to reconsider attending a summit of non-aligned nations in Iran this week, but the Office of the Spokesperson for the Secretary-General has confirmed that Ban will be in Tehran for three days beginning Wednesday.

In an interview with CBC News, Farhan Haq, a spokesperson for the secretary general, confirmed the UN chief received Baird's letter but made clear the UN chief "has certain responsibilities he is determined to carry out."

"His visit does not confer legitimacy," said Haq.

Speaking to reporters in Ottawa on Tuesday, Baird said Tehran will use the presence of the UN chief to advance its own propaganda.

"I just think they're going to exploit his presence there for nefarious purposes," said Baird.

"We're concerned that his presence there will be used to bolster the regime politically. Obviously we wrote in strong terms to encourage him, like a number of our allies did, to reflect on that before he goes."

U.S., Israel oppose UN chief's visit

Ban's decision to attend the summit also drew the ire of the U.S. and continued opposition from Israel.

The Centre for Israel and Jewish Affairs joined with the World Jewish Congress to express "profound disappointment" in Ban's decision to attend the Tehran summit, urging him "to withdraw," in a statement released Tuesday afternoon.

Ban's spokesperson said the UN believes it would be "a lost opportunity" not to make an effort and engage "at the highest levels" with Iran.

The minister told reporters that given Iran's pledge to destroy Israel and its abysmal human rights record, "the UN secretary-general should not dignify that political class with his presence."

According to Ban's spokesperson, the UN chief will convey clear concerns and expectations on issues such as Iran's nuclear program, human rights, and the continued violence in Syria.

In his letter to the UN chief dated Aug. 23, Baird wrote: "Iran's current rulers will use your presence to further their own, hateful purposes. Such a visit would serve only to legitimize and condone the record of this regime, which Canada views as the single most significant risk to global peace and security today.

"As a custodian of the United Nations' charter, I implore you to reconsider this planned visit," said the Aug. 23 letter.

Leaders from 120 countries are expected to gather in Tehran this week for the 16th summit of the Non-Aligned Movement, a group composed of states which do not consider themselves formally aligned with or against any major power bloc.