– The number of women and girls jailed by Afghan authorities for "moral crimes" has risen by 50 percent in the last year and a half, an alarming statistic that reflects the Afghan government's need to step up efforts to protect women's rights, Human Rights Watch said.

The New York-based rights group cited Afghan Interior Ministry statistics showing a sharp rise in the number of women and girls imprisoned for "moral crimes," from 400 in October 2011 to 600 in May 2013. According to Human Rights Watch, the offenses often involve women who are victims of domestic violence or forced marriages and have left home without permission.

Under Afghan law, running away is not a crime. However, the Afghan Supreme Court has told judges to regard as criminals women who flee their homes, the rights group said in a statement issued Tuesday.

"Four years after the adoption of a law on violence against women and 12 years after Taliban rule, women are still imprisoned for being victims of forced marriage, domestic violence and rape," said Brad Adams, Human Rights Watch's Asia director. "The Afghan government needs to get tough on abusers of women and stop blaming women who are crime victims."

Before the U.S.-led invasion of Afghanistan in 2001, the Taliban relied on a strict interpretation of Islam that severely curtailed the rights of women. Women could not go to school or work and could not leave their house without being accompanied by a male relative. Offenders were publicly flogged or executed.

Recently, the Afghan government has overseen reforms that have markedly improved the rights of women. Still, conservative segments of Afghan society continue to put up roadblocks to further reforms. Last weekend, lawmakers balked at passing legislation that bans violence against women and strengthens women's rights.

The law has been in place since 2009, when President Hamid Karzai enacted it by decree. But women's rights advocates want it passed by Parliament to prevent any future leader from striking it down. It came up for a vote in Parliament Saturday, but conservative lawmakers blocked it.

Human rights activists are especially concerned that support for women's rights will continue to erode with the planned withdrawal of most U.S. troops from Afghanistan by the end of 2014. In its statement, Human Rights Watch noted that fewer than half of the country's 34 provinces have a shelter available to women and girls fleeing violence at home. The 18 shelters that exist, the rights group added, "may not be sustainable as they are entirely funded by international donors, and donor assistance is dropping rapidly as the 2014 deadline for the withdrawal of international combat forces from Afghanistan approaches."