Prime Minister Narendra Modi on Wednesday morning arrived in Brussels on the first leg of his three-nation tour to Belgium, the US and Saudi Arabia.During the course of the visit Modi will attend the India-EU summit and the global nuclear security summit in the US.On his daylong visit to Brussels on Wednesday, Modi will hold a bilateral summit with Belgian Prime Minister Charles Michel and then attend the 13th India-European Union (EU) Summit.On March 31, the prime minister will leave for Washington to attend the two-day Fourth Nuclear Security Summit to be hosted by US President Barack Obama.On his way back, he will drop in at Riyadh for a bilateral visit to Saudi Arabia on April 2-3.