The US military is prepared to strike Iran as early as this weekend, though President Donald Trump has yet to make a final decision on whether he’ll authorize such actions, sources familiar with the matter tell CNN.

The White House has been briefed that the military could be ready for an attack by the weekend, after a significant buildup in recent days of air and naval assets in the Middle East, the sources said. But one source cautioned that Trump has privately argued both for and against military action and polled advisers and allies on what the best course of action is.

Top administration national security officials met Wednesday in the White House Situation Room to discuss the situation in Iran, a person familiar with the meeting said. Trump was also briefed Wednesday by special envoy Steve Witkoff and Jared Kushner, Trump’s son-in-law, about their indirect talks with Iran that occurred a day earlier. It was not clear if Trump would make a decision by the weekend.

“He is spending a lot of time thinking about this,” one source said.

Iranian and US negotiators passed notes for three-and-a-half hours Tuesday during indirect talks in Geneva, though they departed with no clear resolution. Iran’s top negotiator said both sides had agreed upon a “set of guiding principles,” though an American official said “there are still a lot of details to discuss.”

White House press secretary Karoline Leavitt said Wednesday that Iran was expected to provide more details on its negotiating position “in the next couple of weeks,” but she wouldn’t say whether Trump would hold off on military action within that timespan. US Secretary of State Marco Rubio is expected to travel to Israel on February 28 to meet with Israeli Prime Minister Benjamin Netanyahu and update him on the Iran talks, a State Department official told CNN Wednesday.