On CNN's Larry King Live yesterday, National Geographic Explorer reporter Lisa Ling said the "highest levels of diplomats" at the State Department have been working to get Lisa's sister Laura Ling and fellow Current TV reporter Euna Lee released from North Korea.

The two were detained on March 17, after North Korea accused them of crossing illegally into the country from China.

Lisa Ling, who is in the middle of a media blitz in advance of the women's June 4 trial date, told ABC's Nightline the two were working on a story about the trafficking of women along the China-North Korea border.

Lisa said she didn't believe they intended to cross into North Korea. "They were expected to be home two days later," she said. "So whatever happened that day, it was not their intention to cross the border."

More, including video of the Larry King Live interview, after the jump.

Lisa Ling appeared by herself on Nightline. On Larry King Live, she was joined by Laura's husband Iain Clayton, Euna's husband Michael Saldate, and the Ling sisters' parents, Mary Ling and Doug Ling.

As she did on the Today show yesterday morning, Lisa re-iterated the families' apologies for any transgressions the women may have made. "If at any point they crossed into North Korea, we profusely apologize on their behalf," she said on Nightline.

Lisa also explained why the families were speaking out now, after having essentially remained quiet since the women were detained: "We've been trying to allow diplomacy to take its course, but given everything that's happening in the news—we're talking about what seems to be a full-blown nuclear standoff, and my little sister and Euna Lee are seemingly in the midst of it—we just felt like it was time to urge our two countries to communicate."

The United States and North Korea do not have diplomatic relations. The Swedish ambassador has made at least two visits to the women since their detention. North Korea conducted an underground nuclear test on May 25. The Associated Press reported that the country is also preparing to launch a long-range nuclear missle capable of hitting Alaska. President Obama and South Korea's president are scheduled to meet in Washington on June 16.

The Nightline interview is available on the ABC News Web site. (Side note: Hey ABC, what's with not making your videos embeddable?)

Larry King Live interview is here: