WASHINGTON—Lawyers for President Trump said they have submitted written responses to questions posed by special counsel Robert Mueller about possible collusion with Russia during the 2016 presidential election.

Jay Sekulow, a lawyer for the president, said the questions were on “Russia-related topics” of the Mueller investigation. Rudy Giuliani, another lawyer for Mr. Trump, in a statement called for the probe to end.

“It has been our position from the outset that much of what has been asked raised serious constitutional issues and was beyond the scope of a legitimate inquiry,” Mr. Giuliani said. “This remains our position today. The President has nonetheless provided unprecedented cooperation. It is time to bring this inquiry to a conclusion.”

The submission Tuesday comes nearly a year after Mr. Mueller first indicated to the president’s legal team that he was interested in questioning Mr. Trump. The answers, largely prepared by Mr. Trump’s lawyers, are likely to be the most direct insight the special counsel will obtain into the president’s knowledge of events during the 2016 campaign.

The president and his lawyers haven’t decided whether he will sit for an in-person interview with Mr. Mueller, but Mr. Trump has said he “probably” wouldn’t.

President Trump, at a post-midterm news conference, responded to questions regarding the Mueller investigation into Russian interference in the 2016 elections, saying "I could have ended it anytime I wanted." Photo: AP

On whether Mr. Trump would sit for an interview, Mr. Giuliani earlier this month told The Wall Street Journal: “I’d have to say ... the lawyers are against it.” He said the team would make a final decision after the written responses were submitted, if investigators “think it’s still necessary.”

“We’re hopeful this will be enough,” he said.

The president’s lawyers declined to let him answer queries about obstruction of justice, an area that Mr. Mueller is also investigating. In particular, the special counsel is examining the president’s decision to fire FBI Director James Comey in May 2017 while the agency’s Russia investigation was under way.

Mr. Trump has denied his campaign colluded with Russia, and Moscow has denied interfering in the 2016 election. Mr. Mueller’s investigation has yielded guilty pleas or convictions from several Trump associates, including former campaign chairman Paul Manafort and former national security adviser Michael Flynn.

Indications have emerged that Mr. Mueller’s investigation is wrapping up, among them the recent departure from his office of a handful of prosecutors. The special counsel has continued to interview witnesses in recent weeks, and Jerome Corsi, who is close to former Trump adviser Roger Stone, said last week he expected to be indicted in the investigation.

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Mr. Trump’s legal team has declined to discuss the written questions they answered for investigators.

This spring, Mr. Mueller outlined for the president’s legal team more than 40 questions he planned to ask Mr. Trump in an interview, according to a person familiar with the matter. Several focused on whether Mr. Trump was aware of contacts between his associates and Russians during the campaign and transition. Mr. Mueller planned to ask the president when he first learned of a June 2016 meeting at Trump Tower with a Russian lawyer linked to the Kremlin that his eldest son, Donald Trump Jr., arranged and several of his top aides attended.

The president’s lawyers have spent the months since then negotiating with the special counsel’s team about the scope and terms of an interview, while publicly waffling over whether to let Mr. Trump sit down with investigators. In the spring, lawyers for the president said they expected him to sit for an interview in mid-July, if Mr. Trump agreed. That never occurred.

More recently, the president and his legal team have focused their efforts on responding to written questions about collusion. Mr. Trump met several times last week with his legal team, the person familiar with the matter said. “I write the answers. My lawyers don’t write answers,” he told reporters in the Oval Office last week.

In fact, his lawyers have been taking the lead writing the answers, in consultation with the president, according to people familiar with the matter.

Write to Rebecca Ballhaus at Rebecca.Ballhaus@wsj.com