Washington, May 9 (DPA) Senator Hillary Clinton, who is battling to keep her head above water in the waning days of the Democratic battle for the presidential nomination, has sent her 'heartfelt congratulations to the people of Israel' on the occasion of the country's 60th anniversary.

But she warned that the 'Jewish state is still not safe'.

'In every generation, Israel faces serious challenges to its security and threats to its existence,' Clinton said in a statement Thursday.

She said if she were elected president of the US, she would 'continue and strengthen' the bonds that have tied the US and Israel together since the US 'recognised Israel at birth'.