Floods killed at least 30 people in north-west Iran as torrential rains hit four provinces. Companies from China and Iran signed the first commercial contracts to redesign an Iranian nuclear plant as part of an international deal reached in 2015 over Iran's nuclear program. Former Iranian President Mahmoud Ahmadinejad was barred from standing in next month's presidential election by the Guardian Council. The European Council extended sanctions against Iran in response to human rights violations. An Iranian Islamic Revolutionary Guard Corps ship had its weapons manned and came within approximately 1,000 yards of the USS Mahan, an American destroyer in the Persian Gulf destroyer. US Secretary of State Rex Tillerson said a government-wide review of American policy on Iran was underway during a meeting with Saudi leaders. Ten Iranian border guards were killed by Sunni militants in a cross-border attack on the frontier with Pakistan. European airplane manufacturer ATR announced on 13 April that it has signed a $536-million deal with Iran Air for at least 20 aircraft. The Boeing Company announced a tentative agreement on 4 April to sell up to 60 737s to Aseman Airlines, an Iranian carrier.