Image caption The emergency contraceptive is effective if taken within 72 hours of unprotected sex

The US administration says it will no longer seek to block over-the-counter sales of emergency contraception to women and girls of all ages.

This means that anyone will soon be able to buy the Plan B morning-after pill without a prescription.

The justice department had fought against a federal judge's order seeking to lift current age and sales limits.

The move is seen as a breakthrough in the 12-year battle to make emergency contraception universally available.

Under current laws, only girls aged 15 and older can purchase the morning-after pill without a prescription.

However in April, US district judge Edward Korman ruled that the drug should be made available over-the-counter and without age restrictions.

Plaintiffs in a federal lawsuit against the Food and Drug Administration (FDA) said the limit unfairly kept women and girls from accessing the drug, which is most effective when taken within 72 hours of intercourse.

US government lawyers had appealed against Judge Korman's ruling, arguing that he had exceeded his authority.

But the justice department has now confirmed that the FDA will drop its appeal and prepare a plan to comply with the ruling.

In 2011, the FDA concluded that the morning-after pill could be safely used by girls of child-bearing age and should be unrestricted.

But US Health and Human Services Secretary Kathleen Sebelius over-ruled the agency, barring girls under 17 from buying the pills without a prescription.

Judge Korman called that rule "politically motivated, scientifically unjustified and contrary to agency precedent".

The FDA dropped this age limit to 15 in April this year.