US Secretary of State Mike Pompeo said this month that the conference would focus on stability and security in the Middle East, including the “important element of making sure that Iran is not a destabilizing influence.”
Lang's trip comes a week after Iran’s Foreign Ministry summoned Polish chargé d'affaires in Tehran, Wojciech Unolt, to provide answers as to why Warsaw had agreed to host the event.
"This is a hostile measure by the United States against the Islamic Republic of Iran, and Poland is expected to avoid assisting the US in holding the conference,” an Iranian Foreign Ministry official told Unolt back then.
The Polish official justified the decision by arguing that the meeting was not against Iran and that Warsaw’s stance towards Iran was different from that of the US.
Iran, however, dismissed the explanation as insufficient, saying that Poland's government would either have to immediately compensate for the move or have Iran "inevitably take reciprocal measures."
US loyalty top priority for Poland
Days before heading to Tehran, Lang called hosting the summit a “success” for his country and told reporters that it would strengthen Poland's strategic partnership with the US.
“The conference has pivotal importance for the Polish-US relations. It is the expression of our strategic partnership and trust. A total of 70 states from all over the world were invited to partake in the conference,” Lang said, according to website Polandin.com.
However, ministers from several European Union countries and EU foreign policy chief Federica Mogherini will likely skip the summit, the Wall Street Journal reported last week.
Under President Donald Trump, the US has stepped up its anti-Iran campaign of pressure, reimposing tough economic sanctions and threatening other countries with severe punishments if they keep trading with Tehran.
Iranian Foreign Minister Mohammad Javad Zarif has called the planned summit a "desperate anti-Iran circus."
Writing on his Twitter account, Zarif said that "while Iran saved Poles in WWII, it now hosts desperate anti-Iran circus." He was referring to Iran hosting more than 120,000 Polish refugees during the Second World War.
Meanwhile, Iran’s Culture Ministry has called off "Poland's Film Week" which was due to be held in Tehran in late January in response to Poland's decision.