Two doctors were shot to death by unknown gunmen in separate attacks in Baghdad on Thursday, amid a surge in violence Iraq in recent months.  A source from the Iraqi interior ministry told Arab Today, that gunmen using weapons with silencers shot one of the doctors whilst he stopped his car near the Samaraie mosque in eastern Baghdad.  A female doctor was also killed in the same manner in the Al-Waleed area of south eastern Baghdad, the source said.  The United Nations has said that more than 2,500 people have been killed in Iraq in a surge of violence from April through June and has called on Iraqi leaders to do what they can to immediately end the bloodshed.  Figures compiled by AFP, meanwhile, showed the death toll in that time was more than twice that of the first three months of the year.  Attacks in recent months have targeted a wide cross-section of Iraqi society - government buildings and security forces were hit by car bombs, mosques were struck by suicide attackers, anti-Qaeda militiamen were shot dead, and Iraqis watching and playing football were killed by blasts.  The surge in violence comes amid a protracted political standoff within Iraq\'s national unity government.  While political leaders have pledged to resolve the dispute, with Prime Minister Nouri al-Maliki meeting his two main rivals last month, no tangible measures have been agreed.  Meanwhile, tensions have continued along a swathe of disputed territory in north Iraq, and months of protests among the Sunni Arab community have continued unabated, albeit in smaller numbers since provincial elections earlier this year.  Analysts and diplomats worry the multifaceted standoffs are unlikely to see any long-term resolution at least until a general election due in 2014.  Additional source: AFP