US STOCKS-Wall St. ends off session highs after fresh Russia probe reports

* Washington Post: WH official of interest in Russia probe

* NY Times: Trump said firing Comey relieved "great pressure"

* Stocks regain some ground lost in Wednesday sell-off

* Strong earnings in focus

* Indexes up: Dow 0.69 pct, S&P 0.68 pct, Nasdaq (Frankfurt: 813516 - news) 0.47 pct (Updates to late close, adds commentary)

By Sinead Carew

NEW YORK, May 19 (Reuters) - U.S. stocks rose but closed below their session highs on renewed concerns about Donald Trump's presidency, after two new reports related to a federal investigation into possible coordination between Russia and Trump's election campaign.

A senior White House adviser is a significant person of interest in the law enforcement investigation of possible Russian ties, the Washington Post reported on Friday, citing people familiar with the matter.

Separately the New York Times reported that Trump told Russian officials at the White House that firing FBI Director James Comey relieved "great pressure" from the ongoing probe. The Times report cited a document summarizing the meeting.

"I'm sure some of (the move) is related to that, and the fact that Trump is going to be out of the country and nobody's quite sure what he's going to do," said Paul Nolte, portfolio manager at Kingsview Asset Management in Chicago.

He added, however, that the market did not seem too concerned as the major indexes were still in positive territory.

"We've got two days now to wring our hands about what might happen," he said.

Trump left on Friday for his first foreign trip since taking office, which the White House hopes will shift the focus away from domestic controversies.

While Wall Street ended higher it failed to fully regain all the ground lost in Wednesday's big selloff after reports earlier this week that Trump tried to interfere in the federal investigation.

Investors have been closely following events in Washington as they worry whether Trump will be able to fulfill campaign promises for fiscal stimulus and tax reform. Many investors saw the policy promises as a key reason for the post-election rally.

The Dow Jones Industrial Average was up 141.82 points, or 0.69 percent, to 20,804.84, the S&P 500 had gained 16.01 points, or 0.68 percent, to 2,381.73 and the Nasdaq Composite had added 28.57 points, or 0.47 percent, to 6,083.70.

But all three indexes clocked losses for the week with the Dow and S&P falling 0.4 percent and Nasdaq off 0.6 percent

All of the 11 major S&P industry sectors ended the day higher. Industrials showed the biggest percentage gain with a 1.36 percent jump while Energy rose 1.24 percent. Oil company shares were boosted by a 2 percent increase in oil futures related to growing expectations that OPEC and other producing countries will agree at a meeting next week to extend crude output cuts.

Some market participants said that for much of the session, they turned their focus to strong quarterly earnings from companies such as Autodesk Inc (NasdaqGS: ADSK - news) and Deere & Co (Hamburg: 924235.HM - news) .

Software (IOB: 0NJS.IL - news) developer Autodesk jumped 14.7 percent and was the biggest percentage gainer on the S&P after reporting better-than-expected quarterly revenue.

Deere hit an all-time high of $122.24 and closed up 7.3 percent at $120.90 after the farm and construction equipment maker posted a better-than-estimated quarterly profit.

Deere helped lift Caterpillar Inc (LSE: 0Q18.L - news) 2.2 percent. General Electric Co was the S&P's top driver with a 2.4 percent rise.

Advancing issues outnumbered declining ones on the NYSE by a 3.13-to-1 ratio; on Nasdaq, a 1.75-to-1 ratio favored advancers.

The S&P 500 posted 26 new 52-week highs and 8 new lows; the Nasdaq Composite recorded 81 new highs and 58 new lows.

About 7.03 billion shares changed hands on U.S. exchanges in line with the average volume for the last 20 sessions. (Additional reporting by Yashaswini Swamynathan in Bengaluru; Editing by Jeffrey Benkoe and Chizu Nomiyama)