Draconian security measures imposed at two landmark monuments in Turkey's biggest city kept US President Barack Obama's many admirers here a good distance away during his visit Tuesday. Two small groups staging anti-US protests meanwhile were comfortably outnumbered by the riot police. Obama got a largely warm welcome when he visited the Hagia Sophia church and the Blue Mosque in the ancient heart of the city, even if the tight security meant people had to scramble onto nearby balconies just to catch a glimpse him. Accompanied by Turkish Prime Minister Recep Tayyip Erdogan, Obama toured the Hagia Sophia church, a 6th-century masterpiece of Byzanthine architecture, converted to a mosque when the Ottomans conquered Istanbul in 1453. The edifice - featuring both Islamic scriptures and biblical mosaics, which were preserved over the centuries under a paint cover ordered by the sultan - was finally transformed into a museum in 1935. Taking a brief walk across the square, Obama took off his shoes before stepping into the 17th-century Sultan Ahmed Mosque, better known as the Blue Mosque for its distinctive tileworks. The mufti of Istanbul guided Obama inside the grandiose building. Obama smiled when he was shown a dome scripture mentioning Prophet Mohammed's grandson Hussein, his middle name given to him by his Kenyan father. The president listened attentively to his guide and admired the 21,000 tiles covering the walls, painted in the delicate Iznik style with a dominating blue colour. In a question and answer session with Turkish college students, Obama said change was slow process, while he appealed to the world to put aside stereotypes and misconceptions. “The world will be what you make of it,” Obama said. “You can choose to make new bridges instead of new walls.” “You will find a partner and a friend in the United States of America.” At Taksim Square, the heart of modern Istanbul about four kilometres away, about 300 people protested US policies in the region in a far-left demonstration. Shouting “Obama, go home” and “We will defeat imperialism,” they marched in the area under close scrutiny from riot police, who outnumbered the protestors. “I do not believe a single word he says. Obama is a typical symbol of imperialism,” said one of the demonstrators, 24-year-old Mehmet, before joining his fellow activists chanting “Yankee go home!”