People look at the shoe at the shooting site in the Iranian parliament in Tehran, Iran, on June 7, 2017. At least 12 people died in the twin attacks by militants against Iran's parliament and Imam Khomeini Shrine in capital Tehran on Wednesday, Iran's Interior Ministry said in a statement. (Xinhua/Stringer/Foroogh Alaei)

UNITED NATIONS, June 7 (Xinhua) -- UN Secretary-General Antonio Guterres Wednesday strongly condemned the terrorist attacks on the mausoleum of Ayatollah Ruhollah Khomeini and the Parliament (Majlis) building in Tehran, capital of Iran.

"He extends his sincere condolences to the Government of the Islamic Republic of Iran and the families of the victims and wishes a speedy recovery to those injured," Stephane Dujarric, spokesman for Guterres, said in a statement.

The secretary-general hopes those responsible for this unjustifiable violence will be swiftly brought to justice. All countries must work together in fighting terrorism while upholding the universal rights and values that bind the global community, the statement said.

On Wednesday, Two simultaneous terrorist attacks struck Iran's parliament and the mausoleum of Ayatollah Khomeini, the late supreme leader of the country who passed away in June 1989, killing 12 people and wounding 42 others, according to media reports.

The twin assaults were claimed by the Islamic State, which would be the first known to have been carried out by the radical Sunni group in mostly Shiite Iran.