The United States and Russia are broadly in agreement about a new treaty to reduce strategic nuclear weapons. The White House and the Kremlin say only some technical issues remain unresolved.

It is hoped that US President Barack Obama and his Russian counterpart Dmitry Medvedev will sign a new START treaty on 8 April in Prague. It was in the Czech capital a year ago that Mr Obama made a plea for a world free of nuclear weapons.

The developments fit in with President Obama's policy of improving relations with Russia and getting Iran to give up its controversial nuclear programme. The new accord will replace the 1991 START 1 treaty which expired at the end of last year. In it, the US and the then Soviet Union agreed to reduce their strategic nuclear arsenals to a maximum of 6000 warheads.