The US State Department put on Tuesday a number of Russian officials connected to the death of lawyer Sergei Magnitsky on a visa blacklist as Moscow threatens to curtail cooperation on Iran, North Korea, Libya and the transit of supplies for Afghanistan if the Senate passes a measure imposing even tougher sanctions for human rights abuses. In comments on the Senate bill issued last week, the Obama administration revealed the threats of retaliation as well as, for the first time, its visa blacklist. “Secretary Hillary Clinton has taken steps to ban individuals associated with the wrongful death of Sergei Magnitsky from traveling to the United States,” the document quoted by The Washington Post said. “Senior Russian government officials have warned us that they will respond asymmetrically if this legislation passes,” the document said. The Russian Foreign Ministry said Monday it would respond to questions on the issue but perhaps not until later in the week, according to the American daily.