The West is facing a “make-or-break” moment to reach a deal with Iran over its nuclear program, Germany’s foreign minister said Tuesday after high-level negotiations again failed to reach a breakthrough.

The statement by Germany — part of a six-nation group in talks with Iran — underscores the growing pressures to achieve at least a general accord before a self-imposed Nov. 24 deadline.

Talks resumed Tuesday in Oman’s capital, Muscat, with various envoys after meetings that included Secretary of State John F. Kerry and Iranian Foreign Minister Mohammad Javad Zarif.

A senior State Department official described the tenor of the Kerry talks as “tough, direct and serious” but declined to characterize them as productive. The official said, however, that negotiators still think it is possible to reach a comprehensive accord before the deadline.

Among the many issues is Iran’s level of uranium enrichment, the process to make fuel for nuclear power plants. Iran claims it seeks only reactors for energy and medical research. The United States and its allies fear that Iran’s uranium-enrichment program could eventually be used to produce fissile material for nuclear weapons.

In return for concessions, Iran is seeking an easing of international economic sanctions.

Yet even as negotiators sought compromises, Iran moved ahead with plans for at least two more Russian-built reactors. The deal, signed in Moscow, also opens the door for the possibility of six additional electricity-producing reactors.

Iran’s deputy foreign minister, Abbas Araghchi, said it was possible to reach “an agreement on general outlines” of a nuclear accord before the deadline, but he gave no further details.

“We are not losing hope,” Araghchi was quoted as saying by the Tehran-based ISNA news agency.

In Berlin, German Foreign Minister Frank-Walter Steinmeier said failure to reach an accord before the deadline could set back negotiations by at least two years.

“We have never been closer [to an agreement] than right now. We have an opportunity. It is a make-or-break moment,’’ he said, according to the Reuters news agency.

Kerry planned to brief President Obama on the nuclear talks during an Asia-Pacific summit in Beijing.

Obama also met Tuesday in Beijing with Russian President Vladi­mir Putin, whose government is part of the group involved in the nuclear talks.

In Moscow, Sergei Kiriyenko, the head of Russia’s Rosatom state corporation, signed a deal with Ali Akbar Salehi, Iran’s nuclear chief, to build at least two more reactors in the Persian Gulf city of Bushehr, the site of Iran’s lone energy-producing nuclear plant.

That facility, started by a German firm in the 1970s under the rule of the shah and completed by Russia, became operational last year after repeated delays.

Rosatom said in a statement that construction of the new reactors would be monitored by the U.N. nuclear watchdog group, the International Atomic Energy Agency. No timetable was announced, but Iranian officials have said previously that the country plans to sharply expand its nuclear-generated electricity in the coming decade.

Russia plans to supply nuclear fuel for the new plants as it does for the existing facility at Bushehr.

Carol Morello in Istanbul contributed to this report.