Two US senators have urged President Barack Obama to take a tough line on Tehran in his speech to the UN General Assembly this week as Iran’s President Hassan Rouhani arrives in New York.In a Monday letter to Obama, Democrat Robert Menendez and Republican Lindsey Graham urged the president to keep pressuring Iran over its nuclear program, which Washington believes may seek military purposes and Tehran says has only civilian goals. “Like you, we viewed the election of Hassan Rouhani as an indicator of discontent amongst the Iranian people and we have taken note of recent diplomatic overtures by Iran. However, whatever nice words we may hear from Mr. Rouhani, it is Iranian action that matters,” the two senior senators wrote in their letter. Menendez is the chairman of the Senate Foreign Relations Committee and Graham is an influential Senate voice on international issues, who along with Senator John McCain is urging a regime change in Syria, an Arab country which is has been stuck in a political crisis since two and a half years ago. Rouhani traveled to New York for his debut address at the 68th annual session of the UN General Assembly this week. The Iranian newly elected president is scheduled to deliver his speech Tuesday afternoon, a few hours after his US counterpart Barack Obama takes the podium. Many have anticipated that the two men may cross paths and briefly meet, even if for a minute. While both sides have confirmed there is no official meeting planned, they haven't ruled out the possibility either, a topic which has dominated headline news at the UN and around the world. Tehran and Washington have had no diplomatic relations since the 1979 Islamic Revolution in Iran. Rouhani said, before he departed for the New York, that he would show the true face of Iran to the world at the UN gathering.