Top Democrats on Capitol Hill say they weren't briefed in advance of the U.S. attack on Iran on Saturday, multiple sources familiar with the discussions told Axios.

Why it matters: Democrats left Capitol Hill for the Juneteenth holiday recess without answers to what they said were basic questions about a potential strike against Iran.

• "Cost, duration, risk to our troops, strategy — the basics before we make a decision of this consequence," Sen. Chris Coons (D-Del.), a senior member of the Senate Foreign Relations Committee, told Axios last week.

Zoom in: Sen. Mark Warner (D-Va.) and Rep. Jim Himes (D-Conn.), the top Democrats on the Senate and House Intelligence panels, weren't briefed before the attack, sources familiar told Axios on Saturday.

• Their Republican counterparts were given advance notice.
• Senate Minority Leader Chuck Schumer (D-N.Y.) was given what was described by a source as a perfunctory notice shortly before President Trump's announcement on Saturday night.
• Himes' committee staff received official notification about the strike from the Pentagon only after Trump made the announcement on social media, another source familiar with the events told Axios.

Between the lines: Senators are scheduled to receive a classified briefing on the situation on Tuesday.

• Director of National Intelligence Tulsi Gabbard postponed a scheduled briefing with the Senate Intelligence Committee on Wednesday, as first reported by Axios.

Axios' Andrew Solender contributed to this report.

Go deeper: Congress dodges preemptive confrontation with Trump over Iran