WICHITA, Kansas – Sam Brownback, the conservative Republican governor of Kansas, signed tight restrictions on abortion into law Tuesday in the central US state.

While abortion has been legal in the United States since 1973, opponents have been whittling away at its availability by enacting local restrictions.

One of measures, called the "fetal pain bill," forbids abortions after the 21st week of pregnancy unless the life of the mother is threatened. It is based on the argument that fetuses can feel pain after the 21st week of pregnancy.

The second bill requires minors to obtain consent from both parents before getting an abortion, and requires doctors to provide state officials with more detailed records concerning abortions.

The restrictions are part of a nationwide wave of limits on abortion enacted at the state level by Republicans victorious in last fall's elections.

Nancy Keenan, president of NARAL Pro-Choice America -- a group that advocates for abortion rights -- decried the Kansas measures.

"Bans like this one could deny needed care to women with wanted pregnancies who experience heart-breaking complications such as a fetal anomaly," Keenan said.

"This extreme bill is out of step with the values and priorities on Kansas voters."

Wichita, the largest city in Kansas, has been at the center of the nation's emotional debate over abortion for decades.

In 1991, thousands of abortion opponents traveled here and were arrested during sit-ins in front of abortion clinics.

In 2009, the city again made worldwide headlines when George Tiller, a doctor who ran one of those clinics, was shot to death by an anti-abortion activist.