(CNN) -- The head of a U.N. nuclear watchdog group said Friday a deal with Iran over its nuclear program is likely in January, an agreement that will also allow inspectors to gain access to a military complex where Tehran is believed to be testing nuclear materials.
The news followed reports that the International Atomic Energy Agency wrapped one-day talks in Iran over its nuclear program, widely suspected by the United States and other Western nations as a front for the country's development of nuclear weapons -- a charge Iran has repeatedly denied.
"We have agreed to meet again on 16 January next year, where we expect to finalize the structured approach and start implementing it then shortly after that," IAEA chief inspector Herman Nackaerts told reporters after returning to Vienna, Austria.
The talks between Iran and the International Atomic Energy Agency (IAEA) were aimed at jump-starting negotiations, while allowing agency inspectors to gain access to a military complex where Tehran is suspected of testing nuclear materials.
Access to the Parchin military complex, just outside Tehran, is a key element in the negotiations.
"We have not been given access to Parchin this time. But as you know access to Parchin is part of the structured approach, and we hope as I said that we will implement that shortly," Nackaerts said.
Iran's liaison to IAEA, Ali Asghar Soltanieh, characterized the talks as constructive, according to state-run news agency IRNA. The report stopped short of saying whether the talks included discussion about investigators getting access to Parchin, which was requested at a meeting in November in Vienna, Austria.
The next round of talks were scheduled for January 16, Soltanieh told IRNA. The IAEA also confirmed the talks would continue on that day.
The United States, meanwhile, slapped new sanctions on Iran on Thursday, targeting a handful of companies and individuals it says are providing materials and technology to Tehran's nuclear program.
The sanctions, announced by the U.S. State and Treasury departments, are the latest to target Iran's economy as well as its ability to develop nuclear material.
The sanctions were essential "given Iran's continued intransigence on its nuclear program," said Victoria Nuland, the U.S. State Department spokeswoman.
Among the targets of the latest sanctions is Prof. Fereydoun Abbasi Davani, the head of the Iran Atomic Energy Organization.
Abbasi Davani and his wife survived a car bomb two years ago that Tehran has blamed on Israel. At least four scientists associated with Iran's nuclear program have been killed since 2010.
The companies being targeted with sanctions: FaraTech, the Neda Industrial Group, Aria Nikan Marine Industry, Towled Abzar Boreshi, Iran Pouya, Terjerat Gostar and Tarh O Palayesh.
The sanctions freeze the companies' assets and prohibit business dealings in or with the United States. Companies and banks that defy the U.S. sanctions could be cut off from the U.S. financial system, the State and Treasury departments said.
Iran maintains its nuclear program is for civilian energy purposes only. But the IAEA has said it cannot verify whether the intent of the program is for peaceful means.
A number of Western nations have placed economic and arms-related sanctions on Iran since November 2010 when the IAEA said Tehran was pursuing technology that could be used to build nuclear weapons.
Since then, Iran has been hit by the United States and the European Union with an oil embargo as well as sanctions targeting its banks and number of its businesses.
CNN's Saskya Vandoorne reported from London and Chelsea J. Carter from Atlanta.