US sanctions are having a stronger effect on Irans economy than anticipated, President Donald Trumps national security adviser John Bolton said on Wednesday, pledging further measures against Tehran. "I think the effects, the economic effects certainly, are even stronger than we anticipated," Bolton told a press conference in Jerusalem. "We are going to do other things to put pressure on Iran as well, beyond economic sanctions," he said without elaborating. Bolton was asked whether the United States had discussed any plans with Israel on how to capitalize on economic protests in Iran and if the demonstrations posed any tangible threat to the Tehran government. "Just to be clear, regime change in Iran is not American policy. But what we want is massive change in the regimes behavior," Bolton said. The Trump administration re-imposed sanctions this month after withdrawing from the 2015 international nuclear deal with Iran, which Washington saw as inadequate for curbing Tehrans activities in neighboring Middle East countries and denying it the means to make an atomic bomb. The Iranian economy has been beset by high unemployment and inflation and a rial currency that has lost half its value since April. The reimposition of sanctions could make matters worse. Thousands of Iranians have protested against sharp price rises of some food items, a lack of jobs and state corruption. The protests over the cost of living have often turned into anti-government rallies. During the press conference, Bolton slammed Tehran’s regional activity. "Iranian activity in the region has continued to be belligerent: what they are doing in Iraq, what they are doing in Syria, what they are doing with Hezbollah in Lebanon, what they are doing in Yemen, what they have threatened to do in the Strait of Hormuz," he said. Bolton arrived in Israel on Sunday for three days of talks focusing mainly on Iran and its presence in Syria.