American forces were able to reach the wreckage of a U.S. Air Force jet in Afghanistan overnight to retrieve remains, but it remained unclear what brought the high-tech aircraft down in Taliban territory the previous day.

The Taliban claimed it shot the plane down, and while a U.S. official said Monday that initial information brought "no indications the crash was caused by enemy fire," a U.S. military spokesperson told CBS News national security correspondent David Martin the cause of the crash was still under investigation. The Pentagon has not officially ruled anything out.

U.S. officials told Martin the pilot of the Bombardier E-11A declared an in-flight emergency shortly before the crash. U.S. helicopters were finally able to reach the crash site overnight to recover the bodies of two crewmen.

A spokesman for the police in Ghazni province, where the plane came down, told CBS News on Tuesday that even Afghanistan's domestic forces had been unable to reach the crash site, which was under Taliban control. The spokesman, Ahmad Khan Sirat, told CBS News' Ahmad Mukhtar that Afghan forces clashed with the Taliban overnight, causing no casualties but blocking the security forces' access to the site.

Sirat told CBS News that Afghan forces were planning Tuesday for an operation along with foreign partners to reach the crash site by ground, but he did not provide any further details.

The plane came down in a remote area in central Afghanistan that is under the control of the Islamic insurgency. Videos quickly emerged on social media purportedly showing the wreckage of the plane — with U.S. Air Force markings — charred and burning.

Martin says the E-11A is a relatively large plane with a crew of just two people – the rest of the aircraft was crammed with state-of-the-art electronics, and now that the bodies have been recovered the main concern is protecting all the technology that went down with the jet.

The plane is normally used for electronic surveillance and can fly at high altitudes with an extended range. The E-11A is often referred to as "Wi-Fi in the sky," and is used to facilitate battlefield communications for American forces and their allies in a region with difficult terrain.

U.S. and Taliban officials have been working to broker a ceasefire or at least to reduce hostilities in the country. There are an estimated 13,000 U.S. troops based in Afghanistan.