* TSX down 20.27 points, or 0.13 percent, at 15,088.70 * Six of 10 main index sectors decline * Valeant slips after Allergan advises against deal * SNC climbs after acquisition move By John Tilak TORONTO, June 23 (Reuters) - Canada's main stock index slipped on Monday as worries about political instability in Iraq and concerns about high valuations dragged on market sentiment, offsetting gains in the index's mining-heavy materials group. In Iraq, U.S. Secretary of State John Kerry met Iraqi Prime Minister Nuri al-Maliki to push for more inclusive leadership as government forces abandoned the border with Jordan, leaving the entire Western frontier outside government control. Investors also digested data showing an expansion in Chinese factory sector activity in June for the first time in six months as new orders surged. Some fund managers fear the Toronto market, which had its highest-ever close last week, might have run ahead of itself. The benchmark index is up about 11 percent this year. "We're skirting pretty close to record highs, so we're going to see some profit-taking," said Michael Sprung, president of Sprung Investment Management. "There's very little room on the upside right now," he added. The Toronto Stock Exchange's S&P/TSX composite index was down 20.27 points, or 0.13 percent, at 15,088.70. Six of the 10 main sectors on the index were in the red. Financials, the index's most heavily weighted sector, gave back 0.4 percent, with Toronto-Dominion Bank losing 0.5 percent to C$54.52 and Bank of Nova Scotia falling 0.1 percent to C$70.83. The materials sector, which includes mining stocks, advanced 1 percent, helped by an increase in copper prices. First Quantum Minerals Ltd jumped 1.4 percent to C$22.03. In corporate news, Allergan Inc advised investors not to sell their shares to Valeant Pharmaceuticals International, which launched a hostile takeover offer for the California-based Botox maker last week. Allergan said Valeant's offer was "grossly inadequate". Valeant shares fell 1.2 percent to C$130.34. Canadian engineering and construction company SNC-Lavalin Group Inc said that it would acquire British energy services provider Kentz Corp for about 1.16 billion pounds ($1.98 billion) in cash. SNC's stock climbed 1.8 percent to C$53.35. ($1=$1.07 Canadian) (Editing by Peter Galloway)