METALS-Copper drifts as US reviews tariffs, firm dollar blunts China PMI lift

June 30 (Reuters) - Copper drifted on Tuesday, as traders held back ahead of possible U.S. tariffs, while a firm dollar countered an expansion in China's factory activity.

The benchmark three-month copper on the London Metal Exchange rose 0.37% to $13,327.50 a metric ton by 0326 GMT, while the most-traded copper contract on the Shanghai Futures Exchange slipped 0.10% to 102,520 yuan ($15,094.67) a ton.

U.S. Commerce Secretary Howard Lutnick is expected to update the president on Tuesday on the refined copper market and domestic refining capacity following a review.

The red metal had so far received some support as concerns over further tariffs had encouraged shipments to the U.S. and tightened availability elsewhere.

Comex copper stocks have been rising since April, after a temporary decline in March. They have risen 3.73% so far in June. They peaked at 664,030 short tons (602,397.88 tons) on Monday.

The U.S. currency, meanwhile, was on track to log the biggest monthly gain in nearly a year, as the market saw a "higher for longer" interest rate scenario to contain inflationary pressure.

A stronger dollar makes greenback-priced metals more expensive for buyers using other currencies. In China, the official manufacturing purchasing managers' index rose to 50.3 in June from 50.0 in May, returning to expansion and beating a Reuters poll forecast of 50.1. A value above 50 is considered a signal of expansion.

The data did little to shift copper decisively higher, as investors remained cautious about China's uneven recovery, with the property sector still weak. Broader risk appetite was also capped by uncertainty over U.S.-Iran diplomacy. Iranian and U.S. teams were expected in Doha this week.

Among other base metals on the LME, aluminium gained 0.40%, zinc added 0.22%, lead dipped 0.18%, nickel rose 1.01% and tin pulled 0.39% higher.

Elsewhere on SHE, aluminium slid 2.04%, zinc dipped 0.21%, lead declined 0.90%, nickel lost 1.71% and tin nudged 0.09% higher.

($1 = 6.7918 Chinese yuan renminbi) (Reporting by Dylan Duan and Lewis Jackson; Editing by Harikrishnan Nair)